A petition calling for a second referendum on UK’s membership of the EU has gained more than one million signatures following the vote to leave.
The petition will be considered by Parliament as it has passed the required 100,000 threshold.
The UK voted to leave the EU by 52% to 48% in Thursday’s referendum but the majority of voters in London, Scotland and Northern Ireland backed Remain.
David Cameron previously said there would be no second referendum.
On Friday he said he would stand down as prime minister by October following the leave result.
The petition, set up by William Oliver Healey, states: “We the undersigned call upon HM Government to implement a rule that if the Remain or Leave vote is less than 60%, based on a turnout less than 75%, there should be another referendum.”
Thursday saw a 72.2% turnout, significantly higher than the 66.1% turnout at last year’s general election, but below the 75% mark suggested by Mr Healey as a threshold.
The Scottish independence referendum in 2014 had a turnout of 84.6% – but there has not been a turnout above 75% at any general election since 1992.
The petition site temporarily went down following “exceptionally high volumes of simultaneous users on a single petition, significantly higher than on any previous occasion”, a House of Commons spokeswoman said.
UKIP leader Nigel Farage, who has campaigned for the UK to leave the EU throughout his political career, said in May that a narrow win for Remain could cause unstoppable demand for a rerun of the referendum.
He said at the time that a result that saw Remain win by 52% to 48% would mean “unfinished business by a long way”.
But Mr Cameron said the referendum was a “once in a generation, once in a lifetime” decision, saying the UK had “referendums not neverendums”.
The parliamentary petitions system is overseen by the Petitions Committee, which considers whether petitions that receive more than 100,000 signatures should be raised in the House of Commons and debated.
The committee is due to sit again on Tuesday.
In a separate petition more than 100,000 people have called on London Mayor Sadiq Khan to declare the English capital independent from the UK and apply to join the EU.
Across all 33 boroughs in London 59.9% of people voted to stay in the EU, with the Remain vote more than 70% in some boroughs.
The page, set up by James O’Malley, states: “London is an international city, and we want to remain at the heart of Europe.
“Let’s face it – the rest of the country disagrees. So rather than passive aggressively vote against each other at every election, let’s make the divorce official and move in with our friends on the continent.”
Mr Khan has said he has no doubt London would “continue to be the successful city” but called for the UK to remain part of the single market.
Former London Mayor Boris Johnson, one of the leading Leave campaigners and the bookmakers’ odds-on favourite to succeed David Cameron, has insisted the UK is not “turning its back” on Europe.
He said the decision would not make the UK any less tolerant or outward looking and would not reduce opportunities for young people.