Prime Minister Sir Keir Starmer has agreed a deal with the EU ahead of a major summit with the bloc, the PA news agency understands.
After Government sources said talks were “down to the wire” on Sunday, there was a major breakthrough.
The deal has now been approved by the EU ambassadors’ committee, it is understood.
The UK has reportedly agreed to 12 years of fishing access for EU boats in UK waters.
There will be no change to current access to fish for coastal communities and no reduction in the British quota or increase in the quota the EU is allowed to catch, it is understood.
Further details of the deal are expected to be announced at the first UK-EU summit on Monday, at which Sir Keir will meet European Commission president Ursula von der Leyen.
Other issues under discussion included defence and security, with reports of talks on a potential agreement allowing British firms access to a 150 billion euro (£125 billion) EU defence fund.
Deals on allowing British travellers to use e-gates at European airports, cutting red tape on food exports, and setting up a youth mobility scheme with the EU, were also thought to be on the table.
Business Secretary Jonathan Reynolds described the deal as a “solid eight” out of 10.
“I’m not the kind of man to get hyperbolic about these things, but look, this is a good deal for borders, for bills, for security in the UK and for jobs,” he told GB News.
Conservative leader Kemi Badenoch criticised the fishing agreement, saying: “12 years access to British waters is three times longer than the Government wanted.
“We’re becoming a rule-taker from Brussels once again.”
Mrs Badenoch and Reform UK leader Nigel Farage had already described the deal as a “surrender” before knowing the details.
Youth mobility could prove a major sticking point for the Opposition, and Mrs Badenoch said she feared it would involve a return to free movement “by the back door”.
The Tories have also set out a series of “red lines” on fishing rights, including ensuring exclusive access to Britain’s territorial sea and resisting “a multi-year agreement which only benefits France”.
The Liberal Democrats meanwhile have called for a new UK-EU customs union.
