Britain will refuse to tell Europe how much it is prepared to pay to settle the so-called “Brexit bill” when Brexit negotiations re-open in Brussels next week, the Telegraph can reveal, in a move that risks plunging the Brexit talks into fresh crisis.

The British move comes as doubts emerged across Europe that Theresa May has the political clout to seal a Brexit deal following her disastrous party conference speech and public disagreements with Boris Johnson.

Senior Whitehall sources said that negotiators will refuse to say which financial “commitments” Britain will honour, setting up a fresh showdown with Brussels.

The UK stance was taken after it became clear EU negotiators will not open talks on a transitional deal and trade talks at this month’s October European Council summit, despite Mrs May’s recent offer to pay €20bn during a transition deal.

“There won’t be any political movement from the British side on the bill until the EU broadens its package to discuss transition and the future relationship,” said a highly-placed UK Whitehall source, adding that the UK would still seek to hold “technical talks” on the bill.