Sir Keir Starmer must offer Europe the protection of Britain’s nuclear weapons amid fears of Donald Trump scaling back security guarantees, diplomats have urged.

EU governments are pushing Brussels to involve Britain in boosting European defence after Friedrich Merz, the man expected to be Germany’s next chancellor, asked for the shelter of British and French nuclear deterrents.

Also on Tuesday, Mr Merz opened talks with the Social Democrats, his likely coalition partner in a future government, to approve an emergency defence fund of €200 billion (£165 billion). The talks aim to find a path around Germany’s tight restrictions on borrowing limits, Bloomberg reported.

Poland, Germany, the Netherlands, France and others want British help in raising finance and ramping up manufacturing, amid fears that Mr Trump could withdraw US security guarantees from Europe.