A Guardian investigation has found that a series of financial transactions involving Reform UK's most senior figures were flagged by banking staff as potential money-laundering concerns and reported to the National Crime Agency (NCA). The revelation widens scrutiny of the party's funding beyond an earlier disclosed £5m gift to leader Nigel Farage, raising questions about whether Electoral Commission rules and the MPs' code of conduct are being followed. It matters because Reform's finances are under intense political and public scrutiny, with cross-party calls for Farage to "come clean".

Bankers filed at least four suspicious activity reports (SARs) with the NCA. One concerns a £1m donation to fundraising vehicle Britain Means Business, apparently from donor Fiona Cottrell, though bank staff were not satisfied the funds ultimately came from her; the NCA has asked a foreign agency to help trace the source. Two relate to a loan from convicted fraudster George Cottrell to deputy leader Richard Tice, made shortly before Tice completed a property purchase and a party donation. A fourth concerns the £5m gift from Thailand-based businessman Christopher Harborne to Farage. SARs are not proof of wrongdoing but prompt closer law-enforcement examination. Tice threatened to injunct the Guardian, while Farage has resigned his Clacton seat to trigger a 6 August byelection, which he will contest largely unopposed.