An online petition demanding the UK to cancel Brexit hit four million signatures on Saturday morning.

The petition will be the most popular ever submitted to the Parliament website if it passes 4.2 million.

The most popular pro-Brexit petition on the Parliament website, which calls on the Government to "leave the EU without a deal in March 2019," has received almost 455,000 signatories.

An online petition demanding that Article 50 is revoked and the UK stays in the EU has now hit four million signatures.

The petition, which has attracted an influx of signatories in recent days, reached the four million mark shortly after 9 a.m. on Saturday.

Backed by dozens of high profile celebrities, it gained support in the wake of Theresa May's speech on Wednesday night, even crashing the Parliament website several times, and Revoke Article 50 began trending on Twitter.

Should it pass the 4.2 million mark, it will be the most popular petition submitted to the Parliament website.

The most popular is currently a 2016 petition calling for a second EU referendum should the winning vote and turnout not reach a certain threshold.

By contrast, the most popular pro-Brexit petition on the Parliament website, which calls on the Government to "leave the EU without a deal in March 2019," has received almost 455,000 signatories.

Read more: Conservative Remainers move to back 'least bad' Brexiteer in battle to replace Theresa May

However, the Prime Minister has ruled out halting the Brexitprocess, saying: "I do not believe that we should be revoking Article 50."

She told reporters in Brussels on Thursday: "If you look back to what happened in the referendum, we saw the biggest democratic exercise in our history.

"And there was a clear result that we should leave the European Union.

"We said here’s the vote, what is your decision, and we will deliver on it.

"And I believe it’s our duty as a Government and as a Parliament to deliver on that vote."

When asked for Theresa May's view on the petition, a No 10 spokeswoman said failing to deliver Brexit would cause "potentially irreparable damage to public trust."

She said: "The Prime Minister has long been clear that failing to deliver on the referendum result would be a failure of our democracy and something she couldn't countenance."

In her Downing Street statement, Mrs May blamed MPs for failing to implement the result of the 2016 EU referendum and told frustrated voters: "I am on your side."

Celebrities and MPs have tweeted their support for Parliament to revoke the Treaty of Lisbon clause that deals with leaving the EU.

Famous figures including actors Hugh Grant and Jennifer Saunders, TV presenter and author Caitlin Moran, physicist Brian Cox and former Labour press chief Alastair Campbell all urged their followers on social media to sign the petition.

Alongside the link, Grant wrote: "I've signed. And it looks like every sane person in the country is signing too. National emergency."