More than two million people have signed a parliamentary petition calling for a second referendum of the UK's membership of the EU.
An unprecedented surge of people trying to access the page briefly caused the official petition website to crash as many Britons shocked by the referendum result tried to engineer a re-run.
By Saturday morning more than one million people had signed - more than ten times the figure at which an issue is formally considered for a debate in parliament.
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."
On Thursday 51.9% of votes were cast to leave the EU, versus 48.1% for remaining part of the bloc.
Meanwhile over 130,000 people signed a petition calling on London Mayor Sadiq Khan to declare the capital independent from the UK and apply to join the European Union.
However elections professor John Curtice said such online campaigns had no chance of success and that a million supporters was "chicken feed" compared to the seventeen million who backed Brexit in the referendum.
A House of Commons spokeswoman earlier said the official petitions site had temporarily crashed due to "exceptionally high volumes of simultaneous users on a single petition, significantly higher than on any previous occasion."
"UK Parliament and the Government Digital Service are aware of the issue and are working hard to resolve the problems as quickly as possible."
It came as a Change.org petition calling on Mr Khan to "divorce" the UK and join the EU gathered more than 139,000 signatures by Saturday morning.
The page, set up by James O'Malley, stated: "This petition is calling on Mayor Sadiq Khan to declare London independent, and apply to join the EU - including membership of the Schengen Zone (Umm, we'll talk about the Euro...)."