The constituency had become a safe Labour seat under Heffer, who was known as being on the left of the party and a member of the Campaign Group. The TrotskyistMilitant group, using entryist tactics was working within the Labour Party, and had gained control of Liverpool City Council in 1982. The city had become a significant base for the group.
When Heffer announced his retirement, Lesley Mahmood, a "Broad Left" councillor and a member of Militant, stood for the Labour nomination. Peter Kilfoyle, who had been the Labour Party organiser in the city since 1985, gained the nomination by a narrow margin; he had been involved in removing Militant influence from the Liverpool Labour Party.[1] Mahmood stood as a "Walton Real Labour" candidate.
Kilfoyle was able to win the election, taking a majority of the votes cast (53.1%), although 11.3% down on Heffer's result in the previous general election. The Liberal Democrats gained from the division in the Labour Party and increased their vote to come second. Mahmood was only able to take a distant third place with 6.5% of the vote. The Conservatives were beaten into fourth, for the first time in Britain since the 1983 Bermondsey by-election, and lost their deposit. They did not place fourth in an English by-election again until the 2004 Hartlepool by-election.
Some of Militant's leaders, Ted Grant and Rob Sewell, had remained convinced of the merits of entryism and argued privately against Mahmood standing.[2] The candidacy was part of the process in Militant's rejection of entryism, or as they saw it, their open turn, and the expulsion of Grant leading to a split in the group.