Britain's position outside the European Union will be marked when London co-hosts the next stage of Brexit negotiations with Brussels after Jan 31.

The rules are due to change as the United Kingdom will become a third-party country on that day and will then have less than a year to clinch a trade deal.

Over the past three years, Brussels has been the location for talks while the UK remains an EU member state.

The UK will stay in the EU's single market and customs union for 11 months after its withdrawal on Jan 31. But it will no longer be a member state and officials in Brussels expect the location of the talks to be split.

The Cabinet Office in Whitehall is the most likely location for the talks, which will involve teams led by Michel Barnier for the EU and an as yet unidentified minister for the British government.

A government spokesman said: "The political declaration makes clear that the UK and EU have to jointly agree the scheduling of talks. More details will be set out in due course."

On Feb 25, EU member states are due to adopt their negotiating position on issues such as trade in goods, fisheries, security and level-playing field demands. Negotiations on the future relationship are then expected to start in early March.

The Guardian newspaper quoted a leaked diplomatic note as saying: "The mandate will contain no surprises and will be based on the political declaration.

"Topics such as fisheries or a level playing field will be discussed (internally) in January. These discussions will be based on slide presentations from the European Commission instead of official drafts. That should give a sense of the sensitivities of member countries and make progress easier."

A summit of EU leaders in June, with which the UK will have no involvement, is expected to be a pivotal point in the negotiations.

Security issues are expected to be a major focus of talks. On fisheries, the political declaration obliges the EU and the UK to make "best endeavours" to agree on future access to British waters by July 1.

"Without an agreement on fish, there will not be a deal－the price for a trade deal is the level-playing field demands and fishing rights," an EU source told The Guardian.