[2] The Social Democratic Party (SDP) had narrowly taken second place in the constituency in 1983, with just over one quarter of the vote.

[1] They stood Mike Hancock, an engineer and member of Hampshire County Council, who had been their unsuccessful candidate in 1983.

[1] They also re-stood their candidate from the previous year, Sally Thomas, a supporter of unilateral nuclear disarmament.

As Portsmouth South was the headquarters of the Royal Navy, this was a significant issue in the campaign.

The Conservative vote fell sharply, while Labour saw only a small increase.