The Scottish Socialist Party was formed in 1998 to contest the first elections of Scotland's new parliament.
It was created after a number of left-wing organisations which made up the Scottish Socialist Alliance aligned to form a single party.
The party advocates proportional representation, abolition of the monarchy and an end to the union through the creation of an independent, Scottish republic.
The SSP achieved electoral success almost instantly when one of its founders, Tommy Sheridan, was elected to Holyrood as a list MSP for Glasgow in 1999.
Mr Sheridan had been the face and the voice of the anti-poll tax demonstrations in Scotland in the 1980s, and was jailed three times over protests against warrant sales, poindings and nuclear weapons.
When he was elected he said: "Sometimes you have to join the establishment in order to change it."
And at the end of 2000 the party's campaign to have warrant sales and poindings abolished paid off when Mr Sheridan's members' bill made it through parliament.
The SSP leader caused a stir in parliament from the start, when he swore the oath of allegiance to the Queen with a clenched fist raised to signal his protest.
He was in parliament for four years before being joined by five of his party colleagues in 2003 - making the SSP the largest left-wing party in Scotland.
It had by this time built up an impressive following on the back of the mass movements opposing the war in Iraq, and secured more than 245,000 votes across the country.
Six MSPs were elected on the regional list: Carolyne Leckie in Central, Colin Fox in the Lothians, Frances Curran in the West of Scotland seat, Rosemary Byrne in the South of Scotland and Tommy Sheridan and Rosie Kane in Glasgow.
It was part of the new "rainbow parliament", known as such because of the number of small parties and independents represented.
The SSP fought for policies such as free school meals and an end to prescription charges - both of which would later be brought in by the Scottish government.
Their MSPs were a colourful addition to the Scottish Parliament.
Rosie Kane held her own protest during the oath ceremony, during which she swore allegiance with the words "My oath is to the people" written on her raised hand.
Colin Fox sang Robert Burns' "A Man's A Man for A' That" as his protest, before being moved to the end of the queue by presiding officer Sir David Steel.
In June 2005, four SSP MSPs were given a month-long ban from the chamber over a protest during First Minister's Questions.
But the real thunderbolt for the party some six months earlier, when the News of the World ran a series of stories about Mr Sheridan, claiming a married MSP had visited a swingers' club and had committed adultery.
Shortly afterwards, Mr Sheridan resigned as convener of the party, citing personal reasons, and announced his intention to sue.
The SSP released a statement paying tribute to the former leader but insisted the party was not a "one-man band".
Mr Sheridan's defamation action ensued, which split the party.
Four MSPs gave evidence against their former leader during his legal action against the newspaper, which he won in 2006, along with £200,000 in damages.
Afterwards, Mr Sheridan described his former colleagues as "scabs" in a tabloid interview and those who had given evidence against him reportedly faced threats and attacks by his supporters.
Mr Sheridan left the SSP after he won the court case and formed another party, Solidarity.
He was later found guilty of perjury, and was jailed for three years at the start of this year.
His former comrades said while this outcome had vindicated them, the socialist movement in Scotland had been very badly damaged in the process.
In the midst of the saga, in the 2007 Scottish elections, the SSP's vote slumped and the party lost all its MSPs.
But it is fielding 46 candidates in all eight regions again this year - including co-conveners Colin Fox and Frances Curran - and hope to regain some of its vote.
The SSP's 2011 manifesto opposes all public spending cuts, which it says is realisable with the introduction of a new local government taxation model, based on income, to raise more from the wealthy.