The Metropolitan Police has launched a criminal inquiry into Reform UK following an undercover Channel 4 News investigation that allegedly showed senior party figures discussing how to disguise illegal foreign political donations. Scotland Yard said it had identified "potential offences requiring investigation" after receiving reports linked to the broadcast, and the matter will be folded into an existing Met Special Enquiry Team probe into donations made to the party. Reform UK denies any wrongdoing and says it will co-operate fully with the investigation, having previously described the report as "the target of a hoax".

The Channel 4 sting reportedly captured discussions involving leader Nigel Farage and others about a £500,000 pledge from a US businessman, routed via his UK-based son, though the donation was never actually made; foreign political donations are banned under UK law. Investigative group Verbatim, which carried out the undercover filming, also alleged Reform accepted £32,500 to fund three opinion polls without disclosing the arrangement or funder. The Met's existing investigation began in February 2025 after an Electoral Commission referral concerning donations ahead of the 2024 general election, with two people interviewed under caution; no arrests have been made and all allegations relate to potential offences under the Political Parties, Elections and Referendums Act 2000, with police liaising with the Electoral Commission and Crown Prosecution Service.