Sir Derek had a majority of 3,675 at the last election, but his constituency boundaries have since been changed to include Tennantry, an area Cllr Ping describes as "at the root of New Labour: middle-class people, nice real ale pubs and lots of Deux Chevaux".
Brighton Pavilion is now a marginal seat as a result - and it is one of several targeted by gay rights campaigners, who believe the "pink vote" can help bring down the Tories. They have already begun to persuade supporters to vote tactically on a scale Britain has never seen before.
Stonewall, the campaign for lesbian and gay equality, has just published its own "gay guide to the general election". More than 100,000 copies of the booklet are to be distributed, through the Stonewall mailing list and publications like Gay Times. Readers can find out how their MP voted on issues such as lowering the age of consent or the ban on gays in the military.
Stonewall supporters will approach election candidates in each constituency with a questionnaire, asking potential MPs to agree, for example, that all citizens should be equal before the law, and that lesbian and gay parents "should be judged by their parenting ability and not their sexuality".
"That way we will go into the next government knowing where we stand with people," says Anya Palmer, deputy director of Stonewall, who wrote the booklet. It urges readers to "vote for the best candidate with a realistic chance of being elected".
OutRage! - the more aggressive gay campaign group - is to campaign in the country's 30 most marginal constituencies. Top of the hit list is the Vale of Glamorgan, where the Conservative Walter Sweeney has a majority of just 19; other target seats include Rochdale, where the Liberal Democrat Elizabeth Lynne is MP, and even Halifax, where the sitting Labour MP is Alice Mahon, who has a comparatively "good" record on gay issues.
Both Stonewall and OutRage! say that their campaigns are apolitical, and aimed at raising awareness. But most seats on the list are Conservative held. Stonewall's guide condemns the Government's record on gay rights, worries that Labour has watered down its commitment to equality, but gives tacit approval to the policies of the Liberal Democrats, Plaid Cymru and the Scottish National Party.
While OutRage! has targeted outright marginals, where even the smallest pressure group could win the day, Stonewall is interested in constituencies where the large number of gay voters is expected to be influential - such as those in Blackpool, Manchester, London and Brighton.
Cllr Ping is one of three openly gay councillors in Brighton. He lives amid the faded grandeur of Regency Square, but looks equally at home in Dr Brighton's, wearing ripped jeans and a black T-shirt advertising a bar in San Francisco. He has two gold stud earrings and a gold-capped tooth. He regularly visits the town's 26 gay bars, clubs and meeting places, distributing free newspapers; he is also the chairman of Brighton's planning committee.
"Lesbians and gay men can feel more at home here than anywhere else I know," says Cllr Ping, who believes they will back his party at the election. Sir Derek Spencer seems unconcerned, saying: "People of various sexual orientations are of all political persuasions and none."
His agent, Pat Smith, says people are more inclined to vote according to their view of the economy than their sexuality. "Quite a lot of the gay community votes Conservative ... or so I'm told."
Her Labour counterpart, Keith Day, is equally unsure of the existence of a gay lobby in Brighton Pavilion, let alone its power, but he says his party is "the glad recipient of anybody's vote". The Labour candidate is David Lepper, a former mayor of Brighton. The Liberal Democrat, Ken Blanchard, is expected to come third.
Andrew Medhurst, a gay man who lectures in the School of Cultural and Community Studies at Sussex University, says one problem with trying to mobilise the gay vote is that many young men and women do not think about their sexuality in political terms. "They think it's about getting ripped to the tits and dancing.
"The other problem is that there are a lot of conservative lesbians and gays in this town. There are well-off queens sitting in very nice flats who are only ever going to vote Labour when the moon turns green."Reuse content