Update: Here we go again? A petition for a second EU referendum has over 3m signatures, but it's being investigated for fraud

Emma Haslett and Hayley Kirton
Police holds back  an angry mob, screaming abuse,
This is a picture of an angry mob. (Source: Getty)

A petition calling for a second EU referendum has now reached over 3m signatures – meaning it must be considered for debate in parliament.

At one point the online petition, launched by William Oliver Healy, was receiving signatures at such a rapid pace, the website crashed.

"We the undersigned call upon HM Government to implement a rule that if the remain or leave vote is less than 60 per cent based a turnout less than 75 per cent there should be another referendum," it says.

Read more: Here's why a petition for a second referendum is a "waste of time"

Legally, it would be possible to throw out Friday's result and start fresh with a new vote, as the referendum was advisory, rather than binding, in nature.

However, Sir Paul Jenkins, a barrister at Matrix Chambers and former government chief legal official, told City A.M. that he thought "politically it would be impossible to ignore it", adding: "it's not legally binding but it is politically hugely important".

Jenkins also remarked that holding another referendum would need to be legislated for itself. For example, yesterday's vote was set out in law by the European Union Referendum Act 2015, which took over half a year to completely make its way through both Commons and Lords.

"You can't just have a referendum plucked out of the air," Jenkins said.

A map of the petition suggests the majority of signatures came in London – one of the UK's few Remain strongholds.

Petitions on the parliament website which reach over 100,000 signatures are considered for debate, while those which get over 10,000 will receive a government response.

However, the Petitions Committee announced today it has launched an investigation into the second referendum petition for fraud, and has warned that it will be removing any fraudulent signatures it finds.

Previous petitions to hit 100,000 signatures include one calling for the legalisation of cannabis, and one aimed at banning Donald Trump from the United Kingdom (Trump is making a well-timed visit to Scotland today).

This morning the Leave side narrowly won the referendum with 51.9 per cent of the vote, versus a 48.1 per cent for Remain.

Earlier this morning David Cameron resigned as Prime Minister, saying it would "not be appropriate" for him to be involved in negotiations.