The SSP was formed out of the Scottish Socialist Alliance (SSA) in 1998. The SSA had itself only been formed in 1996 out of an alliance of various leftist groups operating in Scotland. The SSA's formation was driven by Scottish Militant Labour (which had itself formed out of the Trotskyist Militant Tendency in the early 1990s). Other participatory groups included, amongst others the Scottish Republican Socialist Party (SRSP) and the Communist Party of Scotland a remnant of the Communist Party of Great Britain.
The SSA had performed fairly well in the sixteen seats they contested in the 1997 General Election and this prompted moves to formalise the alliance into a new political party. Again, the driving force was Militant Labour and in 1998 it was agreed to form the SSP.
In 1999 the SSP (in their first ever nation-wide electoral contest) polled fairly well in that years Scottish Parliament election. They did however get less votes than Socialist Labour (a UK-wide party of the left led by Arthur Scargill which has consistently refused to countenance the idea of joining forces with the SSP). None the less the elections to the Scottish Parliament went better than many expected with Sheridan being elected to represent Glasgow.
The period since then has been one of sustained growth for the SSP, including a significant boost to membership when the Socialist Workers Party (SWP) in Scotland agreed to become part of the SSP, although the decision to absorb the SWP remains controversial. They have also picked up many former members of the Labour Party and the Scottish National Party (SNP) who have become disaffected with the way in which those parties now operate.
This period of growth has been marked by some internal disagreements. This is largely due to the nature of the diverse origins of the party. Major disagreement has surrounded the party policy of independence for Scotland, a central policy of the SRSP when it was active, largely accepted by Scottish Miltiant Labour, but argued against by the SWP on internationalist grounds.
Internal party organisation almost positively encourages this high level of disagreement though as the party (unlike most others) allows for the organisation of internal factions (which it describes as platforms). The SRSP has therefore become the Scottish Republican Socialist Movement and the SWP, the Socialist Workers Platform.
The party has become the foremost far-left force in Scottish Politics polling significantly better than the Socialist Labour Party in the 2003 Scottish Parliamentary Elections. Indeed, many would argue that not only are they the most significant far-left force in Scotland, but across the whole of the United Kingdom as well. Their success since formation certainly played a major part in the formation of the Socialist Alliance in England which has links with the SSP, but has not yet been able to make a similar significant breakthrough south of the border.
Their electoral peformance has indicated that whilst it was the Labour Party that most thought they would be challenging, it has in fact been the SNP vote that has been affected by the emergence of the SSP.
They distribute a weekly newspaper, the Scottish Socialist Voice.
The SSP managed to return six members to the Parliament in 2003:
There was a previous Scottish Socialist Party that was in no way related to the existent one. Except in so far as its as many of its leaders are within the current SSP.