Jean-Claude Juncker, European Commission president, said the proposed delay “doesn’t make sense”. He was backed by foreign ministers of the EU’s six founding members, who met yesterday in Berlin for emergency talks on Britain’s seismic vote.
Announcing his resignation on Friday, David Cameron said he would leave it to his successor, chosen in October, to trigger the two-year process of negotiations envisaged by EU treaties.
But Germany’s foreign minister, Frank-Walter Steinmeier, said negotiations should begin “as soon as possible” and Britain had a responsibility to work with the EU on exit terms.
And his French counterpart, Jean-Marc Ayrault, agreed there was “a certain urgency, so that we don’t have a period of uncertainty, with financial consequences, political consequences”.
Ayrault said that in order for the UK to proceed with its exit “they must designate a new prime minister, which would certainly require several days”.
German chancellor Angela Merkel said it “shouldn’t take forever” for Britain to deliver formal notification of its intention to leave under Article 50 of the Lisbon Treaty.
But she said she “would not fight over a short period of time”, and played down suggestions that remaining EU states would want to punish the UK for its decision, saying there was “no need to be particularly nasty in any way in the negotiations”.
Juncker said Britain’s departure was “not an amicable divorce” and talks should begin “immediately” on wrapping up what was never “a tight love affair anyway”. But the director of the Vote Leave campaign, Dominic Cummings, said it was “unthinkable” to invoke Article 50 before a new PM is in place.
Martin Schulz, the president of the European Parliament, revealed EU lawyers were studying whether it was possible to speed up the triggering of Article 50 of the Lisbon Treaty – the untested procedure for leaving the union.
As the EU’s institutions scrambled to respond to the bodyblow of Britain’s exit, Schulz said uncertainty was “the opposite of what we need”, adding that it was difficult to accept that “a whole continent is taken hostage because of an internal fight in the Tory party”.
With the financial consequences of Brexit causing increasing concern, influential credit rating agency Moody’s downgraded the UK’s outlook to “negative”, warning it was facing “a prolonged period of uncertainty” with implications for the country’s medium-term growth.
Colin Ellis, chief credit officer at Moody’s, said the UK’s credit rating could have an impact on UK households in the long term.
“The government borrowing rate is normally the benchmark – it is the rate at which other interest rates in the economy are set,” he said.
“A lower rating would typically correspond to higher borrowing costs, and that would be felt not just by the government but by businesses and households in the longer term.”
Defence Secretary Michael Fallon denied that Cameron’s decision to defer his exit until the autumn left the government a rudderless ship.
Speaking yesterday during a scheduled visit to an Armed Forces Day event in Lincolnshire with the PM, Fallon said: “The Prime Minister goes on, the government goes on until the autumn, until there’s a new leader and a new government.
“We’ll remain at our posts and we have a big agenda. We were elected only a year ago and we’ve set out fresh legislation which we’re taking through parliament at the moment.”
Fallon said he had spoken to Nato secretary general Jens Stoltenberg and other key allies to assure them Britain will not play a “lesser” role on the international scene after Brexit. Cameron refused to give any interviews at the event.
But French president François Hollande said the UK’s decision had implications for international relations that reach far beyond the shores of the UK.
Meeting United Nations secretary general Ban Ki-moon in Paris, Hollande said: “It is true that for the whole world there is a question mark as to what will happen.
“I very much regret the vote of the UK but I respect it. It is a matter of democracy.”
Hollande indicated he and Ban did not feel withdrawal from the EU would throw Britain’s permanent seat on the Security Council into question, saying the outcome of the vote “has no impact regarding where the UK stands within the United Nations system”.
The comments came as a prominent Leave advocate, Tory MEP Daniel Hannan, came under fire for saying a post-Brexit Britain could still join the single market with its free movement of labour rules.
Hannan claimed this was not a backtrack on campaign promises, as the Leave side had promised to “control” immigration, not end it.
As the shockwaves from the 52 per cent to 48 per cent Brexit win continued to reverberate, Tory Remain backers were getting behind Home Secretary Theresa May as the best-placed candidate for a leadership battle with Brexit standard-bearer Boris Johnson.
Former minister Sir Alan Duncan cast doubt on assumptions that the former London mayor was the inevitable choice as Cameron’s successor, saying: “Do not necessarily assume that he is the darling of the Conservative Party activists.
“A lot of them have loved the notoriety and the excitement. But actually, once you scratch the surface a little bit and ask the second question, a lot of them don’t want a permanent ride on the big dipper.”
There have been protests across the UK, including in Edinburgh, by pro-EU supporters. A UK parliament petition calling for a second EU referendum has also attracted more than 1.5 million signatures.
Following Thursday’s historic vote, leaders of Eurosceptic parties in France, the Netherlands and Italy have already demanded referendums in their own countries. And EU leaders are worried the UK’s decision continues to have a knock-on effect – another reason they want the country out of the EU as soon as possible.
The mayor of Calais has told how she wants changes to a deal which allows Britain to carry out immigration checks on the French side of the English Channel.
Natacha Bouchart said: “The British must take the consequences of their choice,” she said on Friday.
Under the 2003 Touquet deal, Britain can carry out checks in Calais to stop migrants trying to get to Britain.
Bouchart said: “We are in a strong position to push, to press this request for a review and we are asking President Hollande to bring his weight to the issue.”
Yesterday it emerged Barack Obama telephoned Cameron after the referendum result was announced to reassure him of the UK’s special relationship with the United States.