Started by a woman named Margaret Georgiadou, the petition was submitted just over a month ago but gained huge traction late Wednesday night and Thursday morning, with little more than a week to go before the U.K. is set to leave the European Union.

At time of writing, it had garnered over 900,000 signatures. It reads: “The government repeatedly claims exiting the EU is ‘the will of the people.’ We need to put a stop to this claim by proving the strength of public support now, for remaining in the EU. A [second Brexit referendum] may not happen—so vote now.”

Parliament’s petitions site went down repeatedly on Thursday morning, becoming unavailable for hours. Some social media users claimed this was due to a conspiracy to suppress the call for a Brexit revocation, but the truth seems far more mundane—the volume of people trying to sign or monitor the petition has in effect created what cybersecurity professionals call a “denial of service attack.” Basically, the site’s infrastructure can’t cope with the sudden surge of anti-Brexit feeling.

“We know that the Petitions site is experiencing problems due to the number of people using the site. This is a mixture of people signing petitions and refreshing the site to see changes to the number of signatures. We are working to get the problems fixed as soon as possible,” a spokesman for the House of Commons told Fortune.

The petition’s popularity is in part thanks to its promotion on Twitter from celebrities such as actor Hugh Grant and musician Annie Lennox.

I’ve signed. And it looks like every sane person in the country is signing too. National emergency. Revoke Article 50 and remain in the EU. – Petitions https://t.co/tPgkaz1soi

— Hugh Grant (@HackedOffHugh) March 20, 2019

I have just signed this petition to #RevokeArticle50 it’s currently gaining 100k signatures an hour!

Please join me, sign & share (the site keeps crashing under the traffic so stick with it) https://t.co/U7mTUBM5xo

— Annie Lennox (@AnnieLennox) March 21, 2019

It’s also a function of the frustration Brits are feeling over the Brexit process, which all seems to be going wrong. The current state of affairs is as follows:

Prime Minister Theresa May has twice failed to get Parliament to back her negotiated Brexit deal with the EU, and she wants to put it to a third vote. The Speaker of the House, John Bercow, however, has said he won’t allow it unless her motion is substantially different from the last attempts.

Meanwhile, May has asked the other EU countries for a three-month extension to Brexit, until just before the newly-elected European Parliament starts work at the beginning of July. She’s meeting with the other heads of state on Thursday, but they are reportedly set to reject her request, offering only an extension until the day before the European Parliament elections take place on May 23—and only if the British Parliament approves her deal.

May addressed the nation on Wednesday, offering no changes to her plan while blaming lawmakers for not approving her deal. Members of Parliament are now reportedly being advised to leave Parliament by cab rather than public transport, to avoid being assaulted by the public. As should be obvious, the implicit threat to their safety has not made the prime minister more popular in their eyes, and May now seems less likely than ever to secure their backing.

So, late next week Friday, the U.K. will crash out of the EU without a deal unless: Parliament approves May’s deal; it rejects the deal and she asks for a much longer extension that involves the U.K. fielding candidates for the European Parliament elections; May is ousted by her Conservative Party and replaced by a hardcore Brexiteer such as Boris Johnson who doesn’t mind the no-deal scenario; the government collapses; or the U.K. revokes Article 50 and effectively cancels Brexit, as the petition is demanding.

“I became like every other Remainer—very frustrated that we’ve been silenced and ignored for so long,” Georgiadou told the BBC. “So I think now it’s almost like a dam bursting, because we’ve been held back in a sense—it’s almost like last chance saloon now.”