MI5 chief rebukes Burnham over Russia-Brexit claims as business groups urge EU reset to be top priority

MI5 director general Ken McCallum publicly rebuked Andy Burnham after the prime minister claimed Russia had successfully interfered with the 2016 Brexit referendum, warning politicians not to overstate Moscow's impact. Downing Street was then forced to confirm it considers the referendum result valid, leaving Burnham's Brexit messaging in tatters just three months into his premiership. The British Chambers of Commerce has urged Burnham to make repairing Brexit's economic damage his top priority, with Shevaun Haviland warning the current EU trading deal is not working for businesses.

Economists estimate Brexit has cost the UK economy up to £240bn, with per-capita income running 6% to 8% below what it would otherwise have reached.

Burnham has pledged to honour the referendum result and abide by Labour's manifesto commitments, which rule out membership of the single market, customs union and freedom of movement — while stopping short of permanently closing the door on reversing Brexit.

Nationalist parties are reportedly 'smelling blood' over Burnham's confused EU positioning, handing Nigel Farage and Kemi Badenoch a potent wedge issue ahead of 2029.