There was a debate with the Militant Tendency as to whether or not to cease working within the Labour Party and the majority of the group decided to do so, although a minority around Ted Grant broke away to form Socialist Appeal. This debate ran alongside a parallel debate on the future of Scottish politics. The result was that the experiment of operating as an "open party" was first undertaken in Scotland under the name of Scottish Militant Labour. This initiative would eventually lead to the foundation of the Scottish Socialist Alliance. The majority of Scottish members then broke away to form the core of the Scottish Socialist Party.
Since ending their short tenure in the Socialist Alliance, the Socialist Party has run candidates in elections as Socialist Alternative. They have three councillors in Coventry and two in Lewisham, South London.
The Socialist Party is a much smaller organisation than the Militant of the 1980s. Under the leadership of Peter Taaffe, their policies have remained close to the Trotskyist mainstream. Their demand for the nationalisation of the one hundred and fifty top British companies and occasional claims of a parliamentary road to socialism have led some critics to label them as reformists.
The Socialist Party is affilliated to the Committee for a Workers International, and is indeed the largest of its forty members.