More than 1.8 million people have signed an online petition hosted by the UK government calling on the for a new European Union membership referendum, 24 hours after Britain voted to leave the bloc. If a petition hosted on the UK reaches 100,000 signatures it is considered for debate in Parliament.

Set up by William Oliver Healey, the petition 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."

Of the 72.2% of the UK population who voted, 51.9% said they wanted to leave the EU, compared with 48.1% who wanted to remain. The vote for Brexit has resulted in the resignation of Prime Minister David Cameron and the pound slumped to its weakest level for more than 30 years.

More than 1.8m people, many from London and the south-east UK, had signed the petition by 3.30pm on 25 June. At 1.30pm around 1.25m people had signed. During the 23 June referendum, 33.57m votes were cast.

London city-state call

Meanwhile, a separate petition calling for London to be declared as an independent city-state has also been backed by more than 100,000 people.

Set up by freelance writer James O'Malley, it calls on the new mayor of London, Sadiq Khan to declare the capital's independence so it can remain part of the EU. It was signed by tens of thousands of people within hours of it being posted.

London was one of the few regions in England and Wales, which voted overwhelming in favour of remaining in the EU. More than 2.2m voted to stay while just over 1.5m backed the Brexit.

Admitting the "Londependence" petition was "mainly done as a joke", O'Malley told London's Evening Standard newspaper: "I thought maybe I could get 200 signatures so the reaction to it has been unbelievable," he said.

He added: "Some people have got in touch with me saying I should make a thing of it."