The pastor using pornography to fan the flames of gay hate in Uganda

The government wants to cool the debate on homosexuality. But influential clergyman Martin Ssempa has other ideas

The congregation was bigger than normal this week at the Christianity Focus Centre in Kampala. Perhaps numbers had been swelled by the prospect of an unusual kind of show-and-tell fast becoming the mainstay of the Martin Ssempa roadshow.

Uganda's "passionate pastor", as he calls himself, had revelations to share with the 200 or so men, women and children who turned up on Wednesday. His ambition to mark the week with a "million-man march" in support of a parliamentary Bill to further criminalise homosexuality had fallen flat over security concerns. But he had a sideshow quite capable of causing a stir in itself.

"The major argument homosexuals have is that what people do in the privacy of their bedrooms is nobody's business," the squat, shaven-headed preacher said. "But do you know what they do in their bedrooms?"

For the next half an hour or so, he answered his own question with a highly unusual visual aid: a series of black and white photographs from what appeared to be the 1960s fetish scene. The avid Michael Jackson fan, who has impersonated the late star on Ugandan television, flicked through the slides of men engaging in scatological fetishism, giving his horrified commentary. "This one is eating another man's anus," he said, while the crowd by turns gasped, sobbed and fell to the floor.

If the evangelist, son of a rural schoolteacher, was not one of the most influential men in Uganda, the show might have been laughable. As it is, the US-educated pastor and former East African breakdancing champion, who grew up wanting to be a "celebrity", has the ear of Uganda's first lady, Janet Museveni. He numbers David Bahati, the MP who introduced the private members' Bill to combat homosexuality, among his congregation. This is a preacher with influence. His return from the United States, where he met Tracey, his wife and mother of his four children, was his beginning. He says he lost his brother and sister to HIV-Aids, and feared he would also die after a period of teenage promiscuity. Now he is a charismatic champion of abstinence, and one of Uganda's most aggressive proponents of anti-gay laws.

Under foreign pressure, the President, Yoweri Museveni, appears to be quietly backing away from legislation which would make homosexuality punishable by life in prison, and "aggravated homosexuality" (when one partner has HIV) liable to the death penalty. But the pastor has been getting louder by the day.

His latest slideshow stunt earned him widespread opprobrium. But it also got him what he was looking for, worldwide attention. He also turned his rhetorical guns on the White House. "Recently in America, Barack Obama and Hillary Clinton stood up and said, 'How can Uganda make a law against homosexuality?' I want us to tell Barack Obama, who has African ancestry, that in Africa sodomy is an abomination."

The challenge may have won the approval of the congregation, but there are wider signs that the tactic may backfire. His talent for controversy has already lost him at least one prominent supporter, US evangelist Rick Warren, who has been retreating since Uganda's anti-gay Bill started attracting global criticism and now repudiates Pastor Ssema. But at home, that hardly matters. Ssempa – or Martin Ssempa PhD, as he signs himself – claims the support of 95 per cent of the country. Aged 42, but with the energy and mannerisms of a man half his age, he has been described as talking so much you would think he was a politician. In many senses, he is. Since setting up his community church near Kampala's Makerere University he has been studiously building his own youth constituency with a Billy Graham-style sex- and alcohol-free abstinence rally every Saturday night, that regularly attracts 2,000 students.

So Ssempa's stunts are not without their audience. But gays and lesbians should not feel unduly picked on. He also preaches against Islam, feminism, Catholics and Satanists, who, he says, hold meetings under Lake Victoria, where they are promised riches in exchange for human blood, which they collect by staging car accidents. For most people, that would be outlandish; for Martin Ssempa, it is barely out of the ordinary.