European Union leaders will meet on April 29 to collectively agree a Brexit negotiating position ahead of withdrawal talks with Britain, European Council president Donald Tusk has announced.

The timing of the summit will give leaders of the EU's 27 other member states time to consider Mr Tusk's response to UK Prime Minister Theresa May triggering Article 50 on March 29, which he has promised within 48 hours.

The EU27 will then come together at the extraordinary summit in April to agree their position and give European Commission chief negotiator Michel Barnier a mandate for exit negotiations.

The date of April 6 was initially pencilled in for a summit but after the Mrs May delayed triggering Article 50 to the end of the month, despite receiving Parliament's approval to do so on March 13.

Mr Tusk announced the date of the summit on Twitter, adding: "Priority must be certainty, clarity for all: citizens, companies & member states."

The timing of the summit means substantive negotiations will not begin until at least May, giving the UK just 17 months to get a deal, according to Mr Barnier's timetable.

The Frenchman has called for talks to be completed by October 2018 to give time for any agreement to be ratified before the UK leaves, expected on March 29 2019 under the two-year Article 50 process.