The European Commission has agreed that the transition period to a new post-Brexit relationship being sought by the UK should last until the end of 2020, chief negotiator Michel Barnier has said.

The 28 commissioners, including president Jean-Claude Juncker, met this morning to approve guidelines for the EU's negotiating position on the transition drawn up by Mr Barnier, which would see Britain observe EU rules and regulations following the date of Brexit in March 2019 while having no role in deciding them.

In a Brussels press conference, Mr Barnier repeated the commission's position that this must include accepting the jurisdiction of the European Court of Justice and continuing to allow free movement of people to settle and work until the end of the period.

In her speech in Florence in September, British Prime Minister Theresa May suggested that what she referred to as an "implementation period" should last for around two years, potentially stretching into spring 2021.

But Mr Barnier said the commission had agreed that the best date to end the transition would be on 31 December 2020, which marks the end of the EU's multi-year budget.

This would mean a transition of about 21 months.

Mr Barnier indicated he is working to a timetable of reaching a political agreement on the future UK/EU relationship by October 2018, in time for it to be published alongside a new treaty containing the terms of agreement on withdrawal and transition.

His comments made clear that he envisages a document falling some way short of a full free trade agreement of the type being sought by Mrs May.

He said guidelines on the future relationship would be presented for adoption by the leaders of the remaining 27 EU states at a scheduled European Council summit in March.

He added: "We will be working on a new very important document that needs to be finalised by October 2018, parallel to the Article 50 treaty - a political document which will accompany the withdrawal agreement and which should clearly stipulate and outline the shape of our future relationship."