The Government does not need to send a formal letter to European Union leaders in order to begin the UK’s withdrawal from the bloc, EU officials have said.

EU leaders are anxious that the Brexit process should start rapidly following the UK’s referendum, which resulted in a vote to leave the union and the subsequent resignation of Prime Minister David Cameron, who had led the remain campaign.

Mr Cameron’s decision to delay the process and let his successor handle the ramifications of a Brexit has generated frustration among EU leaders, who are now determined to push the UK for a swift termination of Britain’s membership.

EU officials now say triggering Britain’s exit may be done simply by Mr Cameron confirming the will of the British people at the European Council, which he is due to attend next week.

“'Triggering' ... could either be a letter to the president of the European Council or an official statement at a meeting of the European Council duly noted in the official records of the meeting,” a spokesman for the council of EU leaders told Reuters.

“It doesn't have to be written. He can just say it,” another said.

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In his resignation statement following the vote to leave the EU, Mr Cameron said: “A negotiation with the European Union will need to begin under a new Prime Minister, and I think it is right that this new Prime Minister takes the decision about when to trigger Article 50 and start the formal and legal process of leaving the EU.”

Mr Cameron will attend the European Council in Brussels on Tuesday to inform the other 27 national leaders of the outcome of the referendum.

However, a council spokesman said Mr Cameron must be explicit that he is triggering Britain’s exit, if he wishes to formally begin proceedings.

He said: “The notification of Article 50 is a formal act and has to be done by the British government to the European Council.”

“It has to be done in an unequivocal manner with the explicit intent to trigger Article 50."

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