British Prime Minister Theresa May leaves after addressing a media conference at an EU summit in Brussels. AP/Frank Augstein

LONDON — Conservative members of parliament now fear that Theresa May's move to delay Brexit until the end of October will ultimately lead to the complete collapse of the project to leave the European Union.

MPs from across the party increasingly believe the prime minister's decision, which was taken at an EU summit this week, significantly increases the chances of a second referendum and a move to revoke Article 50 altogether.

"I have been saying for weeks that Brexit is hanging on by its fingernails," one MP who belongs to the Brexit Delivery Group, a caucus of moderate Tories who back the prime minister’s deal, told Business Insider.

"I am still of the same view, but there are now considerably fewer fingernails."

Many Eurosceptic MPs in the party believe the tide is turning against them.

"I have been saying for weeks that Brexit is hanging on by its fingernails. I am still of the same view, but there are now considerably fewer fingernails."

"We are rapidly hurtling towards no Brexit," Daniel Kawczynski, a Eurosceptic MP who this week resigned from the European Research Group of hardline Brexiteers, said.

He warned in an interview with Business Insider this week that Conservative colleagues who continued to oppose the deal were "endangering the interests of United Kingdom."

One concern, held by the vast majority of Tory MPs who wish to see Brexit delivered, is that the 6-month delay will, in reality, turn into a rolling series of extensions taken by future governments which will ultimately end in Brexit being canceled.

Talk of reversing the withdrawal process entirely has become a much more mainstream topic of conversation within Westminster, spurred on by the success of a petition signed by 6 million UK citizens calling for Brexit to be reversed.

One Conservative MP said: "There has been a significant shift in the conversation around revocation. It is interesting to see how many of my colleagues are now openly discussing it."

Another MP, who recently resigned from government, told Business Insider this week that while revoking Article 50 was "unpalatable" for many MPs and wasn't "the best way out of this situation," it would be supported by a majority of MPs if the country was hours away from leaving the EU without a deal.

"It's the ultimate backstop," the person said.

Jacob Rees-Mogg, who chairs of the European Research Group recently switched to backing May's deal because of his belief that the Brexit project was slipping away from him. On Friday he tweeted an endorsement of a newspaper article which warned that Brexit-supporting "diehards" should wake from their "no-deal dreams."

The handful of Conservative MPs who have backed a second referendum are also broadly pleased with the move to delay Brexit and believe the chances of what is now being called a "confirmatory vote" on the prime minister's deal are rapidly increasing

"Every day that goes by reduces the momentum of Brexit," said one Tory MP who has called for a fresh vote.

"Politics is all about momentum, about peaking at the right moment. I suspect that moment has now passed."

The MP said "It would have been easier to say: The referendum was four years ago, and the result is no longer valid."