Jeremy Corbyn is among five independent MPs to have formed an Independent Alliance group opposing inequality and war.
The former Labour leader joined four other independents elected in July forming the group, which is the fifth biggest block in parliament.
The other members include Shockat Adam, who defeated Labour frontbencher Jonathan Asworth in Leicester South, as well as Ayoub Khan, Adnan Hussain and Iqbal Mohamed – who all also stood on pro-Gaza tickets.
The group said its aim is to boost the opportunity for the independent MPs to ask questions and hold the government to account.
In a joint statement, the MPs said: “We were elected by our constituents to provide hope in a Parliament of despair.
“Already, this government has scrapped the winter fuel allowance for around 10 million pensioners, voted to keep the two-child benefits cap, and ignored calls to end arms sales to Israel.
“Millions of people are crying out for a real alternative to austerity, inequality and war – and their voices deserve to be heard.
“As individuals we were voted by our constituents to represent their concerns in Parliament on these matters, and more, and we believe that as a collective group we can carry on doing this with greater effect.
“The more MPs who are prepared to stand up for these principles, the better.
“Our door is always open to other MPs who believe in a more equal and peaceful world.”
Mr Corbyn was expelled from the Labour Party despite being its former leader and held onto his Islington North seat as an independent at the general election.
The other MPs were elected largely due to anger at Labour leader Sir Keir Starmer’s stance on the war in Gaza, which has seen Muslim and left-wing voters turn against the party.
The Independent Alliance will make up the fifth biggest parliamentary grouping, holding the same amount of power as Reform UK and the DUP, with more MPs than the Green Party on four.
It will likely pile further pressure on Sir Keir over thorny issues such as the ongoing Israeli assault on Gaza, sparked by the October 7 Hamas attacks last year, and the two-child benefit cap, which the Labour leader said he would scrap before changing his mind.
The Independent Alliance is also calling for Labour to reverse a decision to make the winter fuel payment, worth up to £300 for pensioners, means tested.