Three Conservative MPs have resigned, saying the party's "failure" to stand up to hardline Brexiteers has forced them to take the decision.
Sarah Wollaston, Heidi Allen and Anna Soubry have joined the new Independent Group.
In a joint letter to Prime Minister Theresa May, the MPs said: "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."
It comes hours after Labour MP Joan Ryan became the eighth MP from the party to resign and join the Independent Group.
The move takes the number of Independent Group MPs to 11.
US judge invalidates Trump policies targeting immigrants from 39 countries
NASA reverses evacuation alert order for astronauts aboard space station
WHO announces $518 million six-month plan to fight Ebola
Trump says he does not need deal with Iran to get enriched uranium
UN doubles Lebanon aid appeal as war drives surge in humanitarian needs
China's Xi to visit North Korea in push for deeper ties
Hezbollah rejection clouds Lebanon ceasefire and prospects for ending war
Zelenskyy, in open letter, invites Putin to talks to end the war
