Equal Pay Claims Struck Out Due to Cause of Action Estoppel

OUTCOME: Struck Out

Case Nos. 2406419/2025 2406627/2025 2406421/2025

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EMPLOYMENT TRIBUNALS

Claimants: [redacted]

Respondents:

[redacted] Council

Heard at:

Manchester On: 25 February 2026 Before: Employment Judge Cookson

REPRESENTATION:

Claimant: [redacted] Respondent: [redacted]

RESERVED JUDGMENT ON A PRELIMINARY MATTER

1. The claims brought by Ms [NAME], Ms [NAME] and Ms [NAME] under Section 65(1)(c) are struck out under rule 38(1)(a) of the Employment Tribunals Rules of Procedure because they have been brought unreasonably and are an abuse of process on the ground that the claimants are precluded from pursuing these claims by operation of cause of action estoppel and/or Rule 51 of the Employment Tribunal Rules of Procedure 2024.

2. A costs order is made in favour of the respondents. The claimants must jointly pay the respondents the sum of £6,095.67 plus VAT in respect of costs incurred by the respondents’ legal representatives in relation to this application.

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REASONS Introduction 1. These are three claims which are brought as part of a much large “multiple” claim for equal pay brought by around 2,500 employees against Westmorland and Furness Council, and Cumberland Council, as the successor councils to Cumbria County Council. Initially all of the claims in the multiple were brought naming all three councils. Cumbria County Council, which no longer exits, was quickly dismissed as party. All the claimants in the large multiple claims are represented by solicitors acting either for [NAME] or [NAME]. The three individuals in these particular claims are [NAME] members represented by [NAME] solicitors.

2. At an early stage of the case management process, the legal representatives of both the unions and the respondents agreed on the need to identify the correct respondents for each individual claim in the multiple on the basis that individuals now employed by Westmorland and Furness Council could not have a claim against Cumberland Council, and vice versa. This resulted in claims being withdrawn against the authority who was not the employee’s current or most recent former employer, and on the application of the claimant’s solicitors those claims were subsequently dismissed in accordance with what is now Rule 51 of the Tribunal Rules of Procedure 2024 (“Rule 51”). There was no expression of a wish to reserve a right to bring a further claim.

3. Claim numbers 2412698/2023 brought by Ms [NAME] and 2412559/2023 brought by Ms [NAME] were withdrawn against Westmorland and Furness Council and 2412286/2023 was withdrawn by Ms [NAME] against Cumberland Council. On 9 January 2025 a dismissal judgment under what was then Rule 51 was sent to the parties in respect those claims.

4. It seems that a mistake had made and these three claimants had withdrawn their claims against the wrong council. They had withdrawn their claims against their employing council. [NAME] then made an application to amend their claims to add the authority against whom the claims had been withdrawn as a party under what is now Rule 35. This was identified by the Tribunal, and it was pointed out to [NAME] Solicitors that claims against that “new” party had already been dismissed. That led to an application to reconsider the dismissal judgments that had been made. The reconsideration application was listed to be considered at this hearing, but I have been told that those applications are not now being pursued.

5. On 25 November 2025 new claim forms were lodged on behalf of each of the three claimants, relying on the original ACAS early conciliation number, and in identical terms to the previous withdrawn claims. As is usual in equal pay claims of this nature, there is a single generic ground of claim which is relied on by all of the claimants represented by each [NAME]. I have been told that the subsequent parties’ correspondence, these claimants have clarified that they accept that their claims are res judicata to the extent that they relate to the

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3 period of time covered by the previous claim and renewal applications made in respect of those claims in the usual way, and I have been told that the claimants only seek to bring claims in respect of a claim period postdating the date of their claims although no amended claim has been lodged with the Tribunal or leave to amend sought.

6. The respondents have applied for these claims to be struck out on the basis that they are res judicata and cannot proceed because of the principle of cause of action estoppel. There is also an application for costs in respect of the respondents’ costs in dealing with these claims.

7. I have received written and oral submissions from the parties which are referred to in my explanation for my decision below.

8. How some of the law must be interpreted is disputed and I have discussed that in more detail in my summary of the submissions and explanation of my conclusions. RELEVANT LAW 9. In [NAME] v Staffordshire County Council [1996] IRLR 209, CA, the Court of Appeal held that there was nothing in the principles of estoppel which require that they can only apply in cases where a tribunal has given a reasoned decision on the issue of fact and law. The principles of cause of action estoppel apply to a tribunal claim which is dismissed by a tribunal following withdrawal by a claimant.

10. The Employment Tribunal Rules of Procedure 2024 apply to these proceedings in addition to the Employment Tribunals (Equal Value) Rules of Procedure 2024.

11. Rule 51 provides “Where a claim, or part of it, has been withdrawn under rule 50 (end of claim), the Tribunal must issue a judgement dismissing it (which means that the party advancing it may not commence a further claim against the party responding or replying to it raising the same, or substantially the same, complaint) unless (a) the party advancing the claimant has expressed at the time of withdrawal a wish to reserve the right to bring such a further claim and the Tribunal is satisfied that there would be a legitimate reason for doing so, or (b) the Tribunal believes that to issue such a judgment would not be in the interests of justice” 12. HHJ Taylor considered the effect of what was then Rule 521 in [NAME] v [COMPANY] (UKEAT/0253/19/LA), a judgment to which I will return. He explained that Rule 52 was introduced to deal with a problem that had been

1 the wording has been slightly updated in the 2024 Rules but not in a way which I consider to be material.

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4 identified by Lord Justice Mummery in Ako v [COMPANY] 2002 ICR 899 which noted the distinction between the tribunal rules, then in force, and the approach in the civil courts. Withdrawal of a claim in the Employment Tribunal could result in an order dismissing the proceedings which would give rise to a cause of action estoppel, whereas a party was entitled under CPR to discontinue proceedings, which would not give rise to cause of action estoppel because no final order is made determining the complaint.

13. Rule 52 (and now Rule 51) provides a means by which a claimant can withdraw a claim without a judgment dismissing the claim being made in circumstances where the claimant still intends to pursue the same claim, subject to persuading the Tribunal that the circumstances are appropriate. HHJ Tayler considered that the words in parenthesis in Rule 52 are explanatory, explaining the effect of the common law rule of cause of action for Tribunal parties.

14. Whether further proceedings can be brought after the withdrawal and dismissal of materially the same claim is therefore governed by the application of what is often referred to as the ‘doctrine of res judicata’ (literally translated as ‘a matter judged’). In these three claims it is a specific ‘species’ of res judicata which I have to consider, namely, cause of action estoppel.

15. Res judicata and the related principles were considered by Lord [NAME] in [COMPANY] v Zodiac Seats Limited [2013] UKSC 46. In Virgin, Lord [NAME] analysed the nature, scope and effect of cause of action estoppel amongst other forms/principles of res judicata. He formulated the principle in the following terms ‘Once a cause of action has been held to exist or not to exist, that outcome may not be challenged by either party in subsequent proceedings. This is ‘cause of action estoppel’. It is properly described as a form of estoppel precluding a party from challenging the same cause of action in subsequent proceedings’.

16. Lord [NAME] held that ‘cause of action estoppel is absolute in relation to all points which had to be and were decided in order to establish the existence or non-existence of a cause of action. Cause of action estoppel also bars the raising in subsequent proceedings of points essential to the existence or non- existence of a cause of action which were not decided because they were not raised in the earlier proceedings, if they could with reasonable diligence and should in all the circumstances have been raised.’ Lord [NAME] explained that the purpose of all the principles of res judicata (save with the possible exception of merger) was to limit abusive and duplicative action and stated ‘that purpose makes it necessary to qualify the absolute character of both cause of action estoppel and issue estoppel where the conduct is not abusive’ However, Lord [NAME] went on to say that ‘It may be said that if this is the principle it should apply to the one area hitherto regarded as absolute, namely cases of cause of action estoppel where it is sought to reargue a point raised and rejected on the earlier occasion. But this point was addressed in the [NAME] case and to my mind remains a compelling one. Where the existence or non- existence of a course of action has been decided in earlier proceedings, to allow a direct challenge to the outcome, even in changed circumstances and with

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5 material not available before, offends the core policy against the re-litigation of identical claims.’ Submissions 17. I received written skeleton arguments and detailed oral argument from both parties. I have only sought to briefly summarise those submissions. For the claimants Ms [NAME] reminded me of the wording of the Rule 51 and took me to the authority of [COMPANY] -v- [COMPANY] above. She argues that the three claimants here can only be subject to cause of action estoppel if their cause of action in the new claims is identical to that in earlier proceedings relying on Arnold -v- [COMPANY] [1991] 2AC93.

18. Ms [NAME] has argued that equal value claims must be seen as a species of breach of contract claim. A series of contractual breaches each give rise to a new cause of action upon each contractual breach. The later breach of a clause which has already been the subject of litigation is not subject to cause action estoppel. That is because the law treats each continuing wrong as “accruing fresh”. I am referred to the decision of [NAME] -v- [NAME], [NAME] [2014] EWHC4557 (CH). Ms [NAME] argues that each time the claimants are not paid for their work of equal value that is a fresh breach of the implied equality clause and a new cause of action.

19. Ms [NAME] also refers me to the decision of the Court of Appeal in the case of [NAME] -v- Bainbridge and Others [2008] EWCA Civ 885. In particular she refers me to paragraph 255 of that judgment. Ms [NAME] reminded me that the remedy in an equal pay claim consists of damages for arrears of pay and the modification of the contractual term in question. Tribunals cannot make awards for future damages and that is one reason why claimants in equal pay cases often make renewal applications, as indeed the claimants have done in this case, in order to capture arrears of pay occurring between the date of the issue of the claim form and the final determination of their claims. It is argued that that is the reason that the Court of Appeal in Bainbridge expressly limited their conclusion about when res judicata will apply to claims in respect of the “same pay period”. I have been taken to paragraphs 261 and 263 as examples of this limitation. For example, in 261 it is said “… it is not permissible to allege a new cause of action in respect of the particular pay period in another action under the same head for the same period simply by selecting a different comparator. For a new cause of action for the same period, it would be necessary to bring the equal pay claim under a different head, which would normally involve different [NAME] as well …” (Ms [NAME] emphasis added).

20. Ms [NAME] rightly anticipated that the respondents would rely on the case of [NAME] -v- [COMPANY] [2020] 11 WLUK 518. Ms [NAME] suggested to me that that case was wrongly decided, but in any event she argues that it is distinguishable because the claimant in that case had sought to renew her equal pay claim for the same period as her original claim with a later period of time being claimed in addition. These claimants have confirmed they are not seeking to do that in inter-parties’ correspondence. Further the key

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6 reasoning in the [NAME] decision was about the similarity of the jobs carried out by the new [NAME] (in a “like pay” claim) and the EAT had not addressed the issue of separate claim periods within the decision.

21.

Accordingly, it is argued that cause of action estoppel does not apply if the claim relates to different specified period of employment from the original claim.

22. Ms [NAME], for the respondents, argued that I am bound by the decision in [NAME] and that the analysis in [NAME] is not relevant to my considerations here. She submits that the [NAME] decision is a case about pursuing complaints for like work, work rated as equivalent and/or equal value in respect of the same period of time and that explains the reference to those words that I was taken to by Ms [NAME]. It is not a case involving a withdrawal of an equal value claim. Ms [NAME] argued that I could not attach significance to the words in the [NAME] as suggested. She drew my attention to the analysis in [NAME] about what an equal pay claim is. It is not simply a breach of contract claim in the “ordinary sense”. It must be recognised that it is a claim based on a statutory modification of contract what operates in a way determined by statute not by the usual principles of contract law. That modification arises from a comparison between the work of a claimant and her chosen comparator (s).

23. In terms of what the scope of the new claims submitted by the three claimants, Ms [NAME] argued that I must take the new claims on the face of the pleadings submitted. She pointed out that the pleadings do not refer to a different period of time from the original claims. In fact, the three grounds of claim for the new claims are identical to the grounds of claim attached to the first set of claims in 2023. In that sense the cause of action estoppel is even clearer than it was the case involving Ms [NAME]. No application has been made to the Tribunal to amend the new pleadings in the way suggested in Ms [NAME] submissions and parties’ correspondence.

24. Ms [NAME] argued that I can be satisfied that cause of action estoppel applies because the remedy claimed in the 2023 claims before me is for arrears of pay for the six-year period prior to the presentation of the claims and the benefit of the equality clause to modify the terms of employment from the dates of those claims moving forward. The 2025 claims seek remedy for arrears of pay for the six-year period prior to the presentation of the claims so there is clear and significant overlap. Further the claimants are bringing the same claim as their previous claims, seeking the same remedy by reference to the same work undertaken by them, and the same [NAME].

25. Ms [NAME] referred me to the judgment in [NAME]. She says there is a striking similarity between the factual matrix in that case and the situation before me.

26. I note that in [NAME] the claimant had brought a claim for equal pay, based on like work, in 2015. That claim was withdrawn by solicitors acting on her behalf at the time and the judgment dismissing the claim was issued in 2016. The claimant then brought a further “like work” claim in 2018 naming different [NAME] but not contending that there had been any change in the work

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7 being done by her or her [NAME] compared to the 2015 claim. Significantly however one of the [NAME] she named in her 2018 claim, Dr [NAME], had only worked for the university since 2016. The complaints against three [NAME] had been struck out on grounds that the claims offended the principle in [NAME] v [NAME], but the tribunal judge had not found that cause of action estoppel applied and had refused to strike out the complaint in relation to Dr [NAME], although a deposit order had been made in respect of that complaint. Ms [NAME] had appealed against the strike out decision and the respondent had cross appealed arguing that all the claims should have been struck out because cause of action estoppel applied. That issue on the cross appeal had been considered first by HHJ Tayler. He found cause of action estoppel applied to the whole claim.

27. Bearing in mind those background facts, [NAME] argued that it is inconceivable that HHJ Tayler had not taken into account that [NAME]’s complaint in relation to the new comparator Dr [NAME] sought a remedy for a period of time after the date of the dismissal judgment. He must have considered the same issue.

28. Ms [NAME] disagrees with Ms [NAME] that [NAME] was wrongly decided but points out that I am bound by the EAT’s judgment in any event. Even if I overlook the fact no application has been made to the Tribunal to amend the new pleadings in the three claims, Ms [NAME] argued that limiting the remedy sought does not assist the claimants. [NAME] drew my attention to what HHJ Tayler said in paragraphs 50 and paragraph 57 which I have referred to further below. Discussion and conclusions 29. In paragraph 25 of his judgment in [NAME] HH [NAME] noted that “there was a significant period of overlap for the periods of comparison for some of the [NAME] on in the 2015 and 2018 claims. The Claimant contended that she and her relevant [NAME] … from time to time, were doing “like work” throughout the period of comparison in both claims, being the type of work she had been doing since 2007”.

30. In paragraphs 33 and 34 HHJ Tayler considered what cause of action estoppel is in the context of a like work value claim and he also referred to the judgment in [NAME]- [COMPANY] [2011] ICR 1345 and quoted paragraphs 21 to 23 of that judgment which examines what the significance is of [NAME] and whether they are doing different work. After referring to the decision of Her Honor Judge Eady QC, as she was then, in [COMPANY] -v- [NAME], at paragraph 38 he says this “Accordingly, in determining whether a new claim, or a new cause of action, is being advanced, one has to consider whether there has been a change in the work being done so there is a different type of work for the purposes of the comparison with the new [NAME]”.

31. At paragraph 41 HHJ Tayler noted that Ms B had not contended that there was any material change in the work she or her [NAME] were doing throughout

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8 the period of comparison. Pausing there, I consider that to be significant. The claimants in the three cases I am considering say that they have been doing work of equal value with a long list of [NAME] identified in the schedule, throughout the period of time of their original claims and the period in respect they now say is covered by their new claims, that is after the date of the dismissal judgment and renewal applications. They compare themselves to the same [NAME] in the old and new claims and do not suggest there has been any change in the work that they do nor the work the [NAME] do.

32. In paragraph 43 HHJ Tayler refers to what the employment judge had said in her strike out judgment “the Tribunal preferred the claimant’s argument and it did not accept that as the claims for the period before and after 2015 depend upon establishing the same breach of the same implied equality clause, the judicial decision dismissing the claims in relation to the breach alleged in the 2015 claim had the effect of determining the claimant’s contractual rights post 2015 insofar as those rights depend on establishing that breach. It is theoretically conceivable that post 2015 the respondent could have breached the implied equality clause in respect of Dr [NAME] and the work he carried out, and it would make a nonsense of the equality legislation to prevent the claimant from raising a claim in 2018 due to an earlier claim not involving Dr [NAME] being dismissed”. I note that because this is in essence the same argument that is advanced before me, that the dismissal judgments made in relation to the 2023 claims cannot determine the claimants’ later contractual rights to pay for work of equal value. I consider that this supports [NAME]’s’ argument that HHJ Tayler must have had the time arguments raised here in mind because he rejected the analysis of the employment judge noted above in finding that cause of action estoppel applied.

33. After discussing what like work works means, at paragraph 50 HHJ Tayler said this “for there to be a new cause of action there has to have been a change in the type of work being compared between the claimants and the [NAME]”. At paragraph 57 he noted that “the Claimant did not allege in the 2018 claim that there had been a change in the nature of the work she was doing or in the work that her [NAME] were doing…. There was a substantial overlap in time in which the 2015 and the 2018 [NAME] were alleged to be doing “like work” compared with the Claimant and each other. In those circumstances the only reasonable outcome was that cause of action estoppel precluded the Claimant from raising her claim against all [NAME] in the 2018 claim. Alternatively for the purposes of Rule 52, the 2018 claim was precluded because it was same, or the substantially the same, complaint as the 2015 claim”.

34. Applying those principles to the claims I have to consider here, although the claimants are limiting the scope of the remedy they seek in connection with their new claims, nevertheless these claimants say that they were doing work of equal value to their [NAME] without there being any change in the work being undertaken either by them or their [NAME] during the period they say is covered by the dismissed claims and the new claim. The other claimants in these joined claims say they have been doing work of equal value to the

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9 [NAME] throughout the whole period. These claimants are seeking to bring claims to modify the terms of the contracts by virtue of a modification of the implied equality clause relying on the same work of equal value in relation to the same [NAME] as their claims determined by the dismissal on withdrawal judgments.

35.

Accordingly, I prefer the submissions of Ms [NAME] and consider myself bound by the decision in [NAME] v [COMPANY]. I find that these three claims are precluded by cause of action estoppel and in the alternative by Rule 51 because the claimants here have withdrawn their claims based on the modification of the equality clause by reference to the identified [NAME] and the work they were undertaking and they now seek to bring that claim again albeit seeking remedy for a different period of time. As such I accept the respondents’ argument that these claims are an abuse of process and have been brought unreasonably. Costs 36. The respondents have also brought a costs application in relation to the time incurred in dealing with these three claims and the strike out application. Ms [NAME] suggested that the claimants appear to have conceded that bringing the claims would be unreasonable if they cannot be pursued because of cause of action estoppel and that has not been resisted by Ms [NAME]. Accordingly on the basis that the costs application was not resisted in the event that I accept the respondents’ strike out application and conclude the new claims must be struck out because they are precluded by cause of action estoppel and are an abuse of process, and there is no suggestion that I should consider the claimants’ means to pay in respect of what are [NAME] backed claims, I make an order for the claimants to jointly pay the respondents’ costs in the sum of £6,095.67 plus VAT in accordance with Rule 74.

Approved by Employment Judge Cookson

23 March 2026

JUDGMENT AND REASONS SENT TO THE PARTIES ON

2 June 2026

FOR THE TRIBUNAL OFFICE

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