Damian Warburton v The Chief Constable of Avon and Somerset Constabulary

A claim that was identified informally, including in an unpermitted draft amendment, but was not formally brought before the court remains within the scope of the Henderson v Henderson abuse principle. It is not exempt merely because the opposing party knew of it.

Whether a later claim is abusive requires a broad, merits-based assessment of all the circumstances. This includes the terms and negotiations of an earlier settlement. A valid Part 36 settlement of “the whole of the claim” settles pleaded claims only, but an unpleaded claim may nevertheless be struck out as abusive where the claimant knowingly accepts compensation intended to resolve it and then seeks further recovery by exploiting that limitation.

The appellant sought damages and injunctive relief for alleged breaches of the Data Protection Acts by Avon and Somerset. The allegations concerned personal data held before and after 11 July 2019.

Earlier defamation proceedings between the parties had settled when the appellant accepted a Part 36 offer of £20,000. His proposed amended pleading had included data-protection claims, but permission to amend had not been granted and those claims were not pleaded when the offer was accepted.

Her Honour Judge Bloom allowed the respondent’s appeal from District Judge Ayers and struck out the pre-settlement data-protection claim as a Henderson abuse of process. The appellant’s second appeal challenged both the scope of that principle and the use of pre-settlement negotiations in deciding whether the later claim was abusive.

1. Appeal dismissed unanimously. The pre-11 July 2019 data-protection claim was properly struck out as an abuse of process. The remaining claim concerning retention of one item of data was unaffected.

2. The Henderson v Henderson principle concerns claims or matters which could and should have been formally brought forward for adjudication in earlier proceedings. A claim is not removed from the principle because it was mentioned in correspondence or contained in a draft amended pleading for which permission was never obtained. To recognise a category of claims “raised but not brought” would create an unjustified gap in the control of abusive and duplicative litigation.

3. The principle requires a broad, merits-based assessment. It does not follow automatically from the fact that a claim could have been advanced earlier that a later claim is abusive. The court must assess all relevant public and private interests and decide whether the later proceedings misuse the court’s process.

4. By virtue of the rule explained in Hertel v Saunders, acceptance of the Part 36 offer settled only the pleaded defamation claim. The unpleaded data-protection claim was therefore not res judicata. That did not preclude its strike-out under the distinct Henderson jurisdiction.

5. The judge was entitled, and required, to consider the settlement negotiations. They showed that both parties negotiated on the basis that compensation would resolve the data-protection claims. The appellant knew that the offer reflected such compensation, knew that acceptance did not technically settle the unpleaded claim, and deliberately withheld notice that he would seek further damages. Pursuing further compensation by taking advantage of that known slip was abusive.

• Court of Appeal (Civil Division): Dismissed the appellant’s second appeal in [2023] EWCA Civ 209.
• Luton County Court, Her Honour Judge Bloom: On 20 January 2022, allowed the respondent’s appeal from the district judge, struck out the pre-11 July 2019 claim as an abuse of process, and summarily dismissed most of the later claim.
• Luton County Court, District Judge Ayers: On 14 May 2021, as amended on 29 May 2021, refused to strike out the claim or grant summary judgment.