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Sadiq Khan Palantir: the London mayor has agreed to let his text messages and emails be searched as part of a High Court dispute with Palantir over his move to block a Metropolitan police contract. Palantir had sought the searches after Khan intervened to stop a proposed two-year, £50m arrangement with the Met in May 2026. Mopac treats Khan and more than a dozen officials as custodians for the case; their communications may be reviewed for material relevant to procurement and decision-making. The mayor’s lawyers say Khan was not initially listed but consented to searches after Palantir persisted.
“Mopac did not originally consider it necessary or proportionate for the mayor to be added as a custodian, given that the decision was taken by the deputy mayor for policing and crime; his senior position; and the likelihood that any documents held by him would be held by other individuals."
Joseph Barrett KC
Key takeaways
- Khan has agreed that his text messages and emails will be searched in a High Court dispute with Palantir over a blocked £50m Metropolitan police contract.
- Mopac has designated Khan and more than a dozen Greater London Authority and Mopac officials as custodians whose digital communications may be searched and disclosed.
- Palantir announced in June that it planned to sue after Khan stopped the proposed two-year deal that would have run for 24 months.
- Sarah Brown, Khan’s former director of communications who moved to Downing Street in July, is also listed as a custodian.
Table of contents
Why custodianship now covers the mayor
The High Court was told that the mayor’s office and Mopac first excluded Khan from a custodial list because the operational decision to block the supplier had been taken by the deputy mayor for policing and crime. Palantir pressed for a wider set of custodians, and Mopac consented on what its lawyers described as a pragmatic basis.
A custodian designation means those named will have relevant digital material searched and, where flagged, disclosed to the claimant. The searches will target communications held by the custodians that relate to the procurement and the procurement process, and the parties will then resolve what must be produced under the court’s disclosure rules.
Joseph Barrett KC submitted written arguments explaining Mopac’s original position and its subsequent concession. That filing is now part of the court papers and frames the scope of the disclosure debate the judge will resolve before the trial.
Palantir’s claim and the contract at issue
Palantir’s claim centres on the veto of a proposed two-year supply contract with the Metropolitan police worth £50m, a deal the company said it had been negotiating before the mayor intervened in May 2026. The company has argued that the veto was improper and has sought documents and communications to support its legal position.
Court papers referenced press coverage that linked the mayor’s office to briefings about Palantir’s values and ethics. The company has countered that the procurement process considered only a single supplier and that the decision harmed its commercial rights.
The wider context named in filings notes Palantir’s existing work for foreign and US government clients, a detail cited in submissions that shaped public debate about the Met contract. Palantir framed its lawsuit as a legal remedy after it accused the mayor of putting politics ahead of public safety.
What the searches mean for oversight and next steps
Mopac also wants to see Palantir’s internal documents related to the tender and award process; the company is reported to be resisting disclosure beyond what the court orders. The date range for the searches and the precise custodial list remain to be set by agreement or court direction, so the immediate procedural focus is on scope rather than trial timing.
Sarah Brown, named among the custodians, moved from the mayor’s office to a Downing Street communications role in July and is therefore a focus of the disclosure demands because court filings say she ‘initiated’ briefings about the decision to block the deal. That tie complicates the politics: disclosure could reach correspondence created while she served at City Hall and while in government.
A judge will need to balance privacy and public-interest considerations against Palantir’s commercial claim. The case will test how procurement oversight, mayoral discretion and corporate challenge interact when contract decisions are litigated in public.
| Item | Named in filings | Role | Status |
|---|---|---|---|
| Sadiq Khan | Yes | Custodian; mayor who blocked the deal | Consented to searches |
| Palantir | Yes | Claimant; supplier suing over vetoed contract | Pursuing disclosure |
| Mopac | Yes | Oversight body for large Met contracts | Managing custodial process |
| Sarah Brown | Yes | Former mayoral communications director; now at Downing Street | Named as custodian |
How the case could play out
The case for
- A narrow disclosure order that limits searched material by date or subject could protect private correspondence while giving Palantir the core procurement records it needs.
- If Palantir’s documents are ordered disclosed in part, the company may secure evidence that strengthens its procurement claim and accelerates settlement discussions.
The case against
- Broad searches and wide disclosure could expose sensitive communications from multiple officials, raising privacy and political risks for the mayor and others.
- If the court rejects substantial requests for Palantir’s internal material, the company may press a fact-based trial that prolongs litigation and public scrutiny.
What to be careful about
- Sensitive personal or political communications may be disclosed to a commercial litigant if the court orders broad searches.
- Disclosure fights could delay resolution and increase legal costs for Mopac, the mayor’s office and Palantir.
- Wider access to procurement records could prompt further challenges to other public-sector contracts handled by Mopac or the GLA.
The bottom line
The judge will now have to oversee a detailed disclosure process that balances privacy, public interest and Palantir’s commercial claim. Khan’s consent to searches ends the mayor’s initial exclusion but does not decide what material will be produced; that remains a procedural contest. Both sides are positioning around procurement records and communications from the May 2026 decision. The practical outcome will shape not only the company’s legal prospects over a £50m contract but also how future large public-sector procurements are scrutinised in court.
What to watch
- watch for the High Court to set or list a trial date; no date has been published.
- watch for a ruling on the scope or date range of searches, which will determine how much correspondence must be disclosed; no date has been set.
Frequently asked questions
What communications will be searched?
The court process covers text messages, WhatsApp messages and Microsoft Teams chats held by named custodians, plus other digital communications the parties identify as relevant; the exact date range has not been set.
Why has Palantir sued the mayor?
Palantir filed a claim after Khan intervened to stop a proposed two-year, £50m contract with the Metropolitan police in May 2026, arguing the veto was improper and seeking disclosure to support that claim.
Who else is affected by the disclosure demand?
Mopac has listed more than a dozen Greater London Authority and Mopac officials as custodians; Sarah Brown, the former mayoral communications director who moved to Downing Street in July, is among those named.
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