In a letter to British Prime Minister Theresa May, the trio accused the Conservative Party of abandoning the political centre ground, and said "the final straw for us has been this government's disastrous handling of Brexit".
Wollaston said the Conservatives were no longer the "tolerant, moderate, openhearted" party of the past, but have been taken over by the hard right, which she claimed "is marching us toward the cliff edge of a no-deal Brexit".
With Britain's departure from the European Union due on March 29 and no deal yet agreed on divorce terms, the three politicians accused the Government of "recklessly marching the country to the cliff edge of no deal".
"No responsible government should knowingly and deliberately inflict the dire consequences of such a destructive exit on individuals, communities and businesses and put at risk the prospect of ending austerity".
At a news conference, the three former Conservative lawmakers predicted more defections, saying many lawmakers are known to sympathize with the rebels.
"Brexit has redefined the Conservative Party - undoing all the efforts to modernize it", the three lawmakers said.
MP Heidi Allen spoke about Brexit and poverty. "I don't think I would be able to stay part of a party that was a Brexit party that had crashed us out of the European Union".
Eleven British politicians who have joined new political party "The Independent Group" pose for a photograph after a press conference in Westminster in London, Wednesday, Feb. 20, 2019. "If we don't try, we are surrendering our country and frankly we don't deserve the job that we have".
Adding to the sense of flux is the fact that significant numbers of Britons are starting to define themselves politically more in relation to their views on Brexit than to an affiliation with a political party.
A tweet from the Independent Group welcomed the new members, adding: "Both our parties are broken".
JEREMY Corbyn today to "fight against anti-semitism" in a desperate video amid Labour's turmoil over quitting MPs.
A Labour spokesman criticised the group, saying they had formed "what is effectively an establishment coalition based on the failed and rejected policies of the past", such as austerity, corporate tax cuts and privatisation.
"We no longer feel we can remain in the party of a government whose policies and priorities are so firmly in the grip of the ERG and DUP", they said in a statement.
Ryan announced she was joining the Independent Group because of the "culture of anti-Jewish racism and hatred for Israel" within the party under leader Jeremy Corbyn on Tuesday.
May, like Corbyn, expressed disappointment by their announcement. "I am saddened by this decision - these are people who have given dedicated service to our party over many years, and I thank them for it", she said. "Of course, the UK's membership of the European Union has been a source of disagreement both in our party and our country for a long time".
It is already the most significant breakaway group in nearly four decades for a parliament in which the two main parties have formed the government of the day for nearly a century, largely restricting smaller groups to the political fringes. They will be buoyed by fresh opinion polls showing a respectable initial level of support - 10 per cent, according to Sky Data, though this is nowhere near enough to prosper in a first-past-the-post voting system.