Solidarity party leader Tommy Sheridan yesterday announced he was "stepping aside" after flopping at the Holyrood election.

The disgraced former MSP said he was vacating the leadership to "make more time to concentrate on bringing down Rupert Murdoch and his News Group Newspapers empire".

It marks the latest chapter in a career which saw him rise to prominence while co-convener of the Scottish Socialist Party, in charge when the SSP returned six MSPs in 2003 and won 15.2% of the vote in Glasgow.

However, his decision to sue the News of the World newspaper in 2006 over allegations about his sex life split the SSP and he formed Solidarity in the same year. He won the initial court case, but his reputation suffered a severe blow when in 2011 he was jailed for committing perjury in the initial trial.

Solidarity, which he led with fellow socialist Rosemary Byrne, has failed to match the early success of the SSP.

In 2007, Solidarity slumped to 1.5% of the vote nationally and fell to 0.14% four years later, marginally ahead of the Pirate party.

In May’s Holyrood poll, only 14,333 voters backed Sheridan’s party – a paltry 0.6% of the electorate.

In a statement released yesterday, he explained his decision: "I am not standing down, I am stepping aside. Tony Benn relinquished his seat in the House of Parliament in order to concentrate on politics. I am stepping aside as co-convenor to make more time to concentrate on bringing down Rupert Murdoch and his News Group Newspapers empire.

"I will clear my name and expose the lies told about me in court and in News Group Newspapers. I will not rest until News Group Newspapers is exposed as a thoroughly criminal organisation."

Sheridan is challenging the perjury conviction through an application to the Scottish Criminal Cases Review Commission.

The fading firebrand also represented himself in court recently in a dispute on the original defamation verdict.

A source close to the party said Solidarity had a “very small” number of members and was “sinking fast”.

His resignation will fuel speculation he is to leave politics after failing to win an election in over 13 years.

Ahead of the May election, Sheridan’s wife Gail made clear the Holyrood poll could be his last.

She wrote: “If less than six out of every 100 voters in Glasgow can’t be bothered voting for him, the message will be clear.

"He is not valued enough and we will demand he comes home to us permanently.

“I will fight hard on his behalf but at the end of the day, if the people of Glasgow don’t want him, that’s fine. We do.”

Councillor Pat Lee has been elected to replace Sheridan as co-convener until the party's conference in October. Byrne will continue in her role.

In recent years, Sheridan has appeared on Celebrity Big Brother, took part in charity boxing matches and tried his hand as a comedian at the Edinburgh Festival.