Disputes over fishing rights and future business competition rules have been major hurdles in agreement during months of often fraught talks. Negotiators are now thought to be thrashing out the final details. The official announcement of a deal is expected on Thursday morning.

The document is around 2,000 pages long, and both sides have until 31 December - when the UK leaves EU trading rules - to get it approved by parliamentarians.

A deal would end the prospect of the two sides imposing widespread import taxes - tariffs - on each other's goods from 1 January, which could have affected prices.

EU sources said the UK prime minister and European Commission President Ursula von der Leyen had been in contact in an attempt to break the deadlock before the expected pause in negotiations for Christmas.