He added: “A negotiation with the European Union will need to begin under a new Prime Minister.
“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.”
Speaking three hours later, it was clear Mr Johnson agreed. The former London mayor said: “It’s vital to stress there’s now no need for haste.”
Leave colleague Michael Gove echoed his words, arguing the process would be gradual.
He said: “The British people’s vote to leave is the start of a process and while that process is ongoing our existing trading relationships with the European Union and the rest of the world will continue as before.”
It emerged Germany will push for an association agreement with Britain once it leaves.
According to a finance ministry paper, the plan is to avoid making too many concessions that would encourage other countries to hold their own referendums.
Details of the proposed association agreement are unclear but it would spell out trading rules and other regulations.
The Leave vote caused panic across Europe. Italian PM Matteo Renzi called for the EU to switch direction, tweeting: “We have to change it to make it more human and more just.”
An editorial in leading Italian daily Corriere della Sera said: “Little England won over Great Britain.”
Italian foreign minister Paolo Gentiloni said: “We would have much preferred a different outcome but we respect the
decision. But leave means leave. Great Britain will certainly remain our friend and our ally but the decision to go has been taken and it must be followed up on.”
German chancellor Angela Merkel expressed “great regret” but insisted Europe was “strong enough” to find the “right answers”.
She said the EU had contributed to peace on the continent but that stability could not be taken for granted in a “world of turmoil”. She added: “The idea of European unification was the idea of peace after centuries of horrendous bloodshed. The founding fathers found a way to come together and it was manifested in the Treaty of Rome almost 60 years ago.
“For the future, we should not take this for granted. We can all see that we are living in a world of turmoil.”
Mrs Merkel has invited Donald Tusk, French president Francois Hollande and Italian premier Renzi to a meeting in Berlin on Monday ahead of a scheduled EU summit.
President Holland said the vote should act as a “jolt” to implement “profound change”. He added: “It is a sad decision but one I respect. The vote puts the European Union in difficulties. It must recognise its shortfalls.”
But Far Right parties across the continent welcomed the vote. Many hoped it would ultimately spell the end of the European project.
French National Front leader Marine Le Pen changed her Twitter profile to a Union Jack and later held a press conference with a backdrop which said: “ Brexit – and now France.”
She said: “That which no-one dared to dream about a few months back is now a reality which is clear to everyone. Yes, it’s possible to leave the EU.
“The British people have given to the Europeans, and also the world, a dazzling lesson in democracy.”
She added that the European question would be “at the heart of the next French presidential
elections” in April and May next year, adding: “I’ve been calling for a referendum of the same kind since 2013”. And she repeated her desire to hold a poll after six months of negotiations with Brussels.
She was echoed by Geert Wilders, leader of the Dutch anti-immigrant PVV party. He said: “I congratulate the British people for beating the political elite in both London and Brussels and I think we can do the same.
“The Dutch would like to be in charge again of their own budget, their borders and their immigration policy.
“We should have a referendum about a ‘Nexit’ as soon as possible.”
The German finance ministry said last night it also had concerns about Austria, Finland and Hungary pushing to leave.