Tommy Sheridan has distanced himself further from the Scottish Socialist Party by announcing details of a new party to be launched this weekend.
Mr Sheridan said has taken a further break away from the SSP
Solidarity - Scotland's Socialist Movement is to be led in its first few weeks by the former SSP leader and SSP MSP Rosemary Byrne.
The split will take the number of SSP MSPs at Holyrood down to four.
An SSP spokesman described the new party's launch statement as a restatement of SSP policy.
Glasgow-based politician Mr Sheridan had publicly criticised former allies in the SSP after winning a £200,000 defamation action against the News of the World over allegations about his private life.
Eleven party figures, including leader Colin Fox and MSPs Rosie Kane and Carolyn Leckie, gave evidence against Mr Sheridan during the case.
The announcement for a new party followed a meeting in Edinburgh on Sunday which was attended by more than 70 "leading socialists", according to allies of Mr Sheridan.
He said: "This was an excellent planning meeting conducted in a friendly spirit, a spirit that is reflected in the name that we are recommending as an interim working title.
"We shall be offering solidarity to working people in struggle, to those fighting for an independent socialist Scotland, solidarity to all those opposing Blair and Bush's illegal wars, to all those fighting for social justice and an end to poverty and discrimination."
Ms Byrne added: "This is not a party just for ex-SSP members - it is a new movement that is open to all who share our vision of an independent socialist republic in Scotland and an end to global corporate wars."
The split will also have financial consequences for the SSP.
Official figures from The Electoral Commission last week showed that in the second quarter of this year, the SSP received £38,898 from five of the six MSPs - with Mr Sheridan and Rosemary Byrne accounting for nearly £16,000 of the total.
The new party is currently negotiating with the SSP over the issues of party donations, staff and the ownership of the SSP's HQ building in Glasgow.
An SSP spokesman claimed the party was "largely composed of bitter opponents of Scottish independence in the London-controlled Socialist Workers Party and the Committee for a Workers' International".