British Prime Minister David Cameron has ruled out a second referendum on staying with or leaving the European Union (EU).
He also says he won't start the official process of quitting the EU before he steps down -- despite European leaders pushing for a quick Brexit process.
Mr Cameron also called on the UK to "bind together" in this time of turmoil, in his first address to parliament since he announced his resignation.
David Cameron gone by September
His replacement could be appointed by September, according the Conservative Party, with the government under pressure to fill the vacuum left by Mr Cameron's resignation.
Mr Cameron announced he would resign after Britain ignored his advice and voted to leave the 28-member EU in last week's referendum.
"Although leaving the EU was not the path I recommended, I am the first to praise our incredible strengths as a country," Cameron told parliament.
Britain should negotiate the terms of its exit from the EU before holding its next parliamentary election, the chair of the committee of Conservative lawmakers has said.
Several Conservative lawmakers have urged leadership candidates to try to broker a deal quickly to make any campaign is as painless as possible.
All eyes are on former London mayor Boris Johnson, the most prominent of the "Leave" campaigners.
But not all party members back him and many are pressing for "Anyone But Boris", seeing his decision to back the Leave campaign as a betrayal of his former ally Mr Cameron, according to media reports.
A wave of MPs from the opposition Labour Party have resigned in protest, including his most senior business policy chief who said Labour leader Jeremy Corbyn was partly to blame for last week's vote to leave the EU.
"Too many of our supporters were taken in by right-wing arguments and I believe this happened, in part, because under your leadership the case to remain in the EU was made with half-hearted ambivalence rather than full-throated clarity," wrote Angela Eagle, Mr Corbyn's top business spokeswoman, in a resignation letter she later posted on Twitter.
Ms Eagle was one of at least 16 members of his shadow ministerial team to resign in the last two days. All of those resigning will remain elected members of Parliament.
Finance minister George Osborne said the British economy was strong enough to cope with the volatility caused by Thursday's referendum, the biggest blow to European unity since World War Two.
But his words failed to halt the fall of pound, which later sank to its lowest level against the US currency for 31 years.
Many economists have cut economic growth forecasts for Britain, with Goldman Sachs expecting a mild recession within a year.
Boris Johnson said it was now clear "people's pensions are safe, the pound is stable, markets are stable. I think that is all very good news".
The leaders of Germany, France and Italy have agreed there can be no informal negotiations on Britain leaving the European Union before London triggers the formal application process to leave the bloc, German Chancellor Angela Merkel says.
"We are united that Article 50 must be activated and before this decision is taken no further steps can be taken," Merkel said on Monday with reference to the clause in the European Treaty that begins the process for a country to exit the bloc.
Article 50 is the part of the EU's Lisbon treaty governing the procedure for an exit, and it is up to the departing country to trigger it.
Scotland's devolved government will seek the widest possible backing in the Scottish parliament to keep its ties with the European Union.
In an emergency debate at Holyrood, Nicola Sturgeon will call on MPs to support her talks "for protecting Scotland's relationship with the EU, Scotland's place in the single market".
Commenting ahead of the debate, she said: "I have already made it clear that I regard it as democratically unacceptable for Scotland to face the prospect of being taken out of the European Union against the wishes of the people of Scotland, as expressed overwhelmingly in last week's referendum.
"I am now determined to explore every avenue to retain Scotland's EU status and today's parliamentary debate is a vital part of that process.