Titled “Revoke Article 50 and remain in the EU”, it also has the highest rate of sign-ups on record, according to the official Petitions Committee, adding more than two million signatures in 24 hours.
The official website has crashed numerous times since the petition leapt in popularity on Wednesday, with MPs and celebrities publicly backing the appeal, including Jennifer Saunders, Hugh Grant and Brian Cox.
Parliament considers holding debates about any petition that gets more than 100,000 signatures. However, some remain sceptical about whether they can force changes in government policy.
Here, The Independent looks at the five other most-signed petitions to parliament and whether they have been successful in achieving their aims.
1. Revoke Article 50 (5.5 million signatures so far)
Despite the growing campaign to revoke Article 50, Theresa May has said Brexit will go ahead. Speaking at Downing Street on Wednesday, she blamed MPs for failing to implement the result of the 2016 EU referendum and told frustrated voters: “I am on your side.”
2. Second EU referendum (4.1 million signatures)
This petition, calling for a second EU referendum, was set by a Brexit activist in 2016 before the vote had even taken place, because he feared the Remain camp could win. But after his side’s narrow victory, he said the petition was “hijacked” by Remainers demanding a fresh vote. The government has repeatedly refused to hold a new referendum, saying it is committed to implementing the result.
3. Block Trump’s state visit (1.8 million signatures)
Created the wake of Donald Trump’s victory in the 2016 US election, this petition sought to block him from receiving an official state visit to the UK. It claimed he would “cause embarrassment to Her Majesty the Queen” due to his “well documented misogyny and vulgarity”. The government, however, dismissed the petition and has welcomed Mr Trump for two visits in the past two years, including an audience with the Queen.
4. Give people a Final Say on Brexit deal (1.2 million signatures so far)
Run by The Independent, the Final Say campaign calls for the British people the right to make that all-important decision on the Brexit deal. Regardless of how you voted in the first referendum, you deserve a say on the final deal.
5. Give the meningitis B vaccine to all children (823,000 signatures)
This petition, set up in late 2015, urged the government to roll out its meningitis vaccination scheme to children aged up to 11, arguing that “all children are at risk from this terrible infection”. The Department of Health has yet to extend the programme but argues that it “offers protection to those at highest risk”.
6. Ban Trump from visiting the UK (586,000 signatures)
Also created in 2015, soon after Mr Trump began his presidential campaign, this petition sought to block him from entering the UK due to his “hate speech” against minorities. In a statement the Home Office said it recognised the “strength of feelings against [his] remarks” but did not impose any ban on Mr Trump.