Why's that? I ask vaguely aware that it is no longer Ramadan

"Why's that?" I ask, vaguely aware that it is no longer Ramadan."It's one of the five pillars of wisdom. But I do it two days a week to keep my sex drive down." Ibrahim eyes me disdainfully, warning me off his testosterone The evils of sex - or fornication - are high on his agenda. Ibrahim proselytises urgently about those who indulge in pre-marital sex receiving 80 lashes. Extramarital sex is rewarded with the beating plus public stoning; for "carnality" is reserved for marriage, and then practised with restraint. In Ibrahim's world, instant copulation is only ever a friendly hello away: "If I chat with one of the brother's wives, before you know it she likes me and then ... fornication." He's an enthusiastic supporter of covering 'em up and keeping 'em in, so I am cast as a tool on Satan's workbench. Lovely.There are approximately 20 stalls like this in London.

Black Crescent, which produces the incense, was established by Ismael Hanza, who was inspired by the American Initiative aimed at Black Muslims, part of the Nation of Islam movement. Like their US counterparts, the stalls provide cheap, portable goods which give their workers independence from non-Muslim employment, allowing them to observe Islamic rituals, most obviously salat, the five times daily prayers. There is no pressure to preach, but many of the stallholders do, providing literature or working in pairs, so that one handles the business side while the other cares for the moral concerns."Anyone who practises the religion has the duty to relate it, even if it's only one verse of the Koran," explains Ismael Hanza. "It doesn't matter if you're an accountant or work in a garage It's like Tories and Labour. You can support them privately or you can go to people's homes and tell them about it."Ibrahim has a spiritual monopoly of the railway station, however, and begins to outline a number of increasingly bloodthirsty scenarios ("Imagine you're being raped..." he says at one point).

Retribution is meted out according to the Holy Book's teaching (including decapitation) but in this scheme of things, maiming and violent, messy death are less punishment, more therapy. This justice prevents further sin but, more significantly, cleanses the offenders and allows them into Paradise And Paradise is where it's at. Like those of Christian puritans, Ibrahim's monologue stresses the insignificance of more obvious earthly pleasures. "It's just Satan whispering in your ear," he says of all activities outside prayer.Ibrahim gives example after example of how he would kill his blood kin rather than let them harm a hypothetical Muslim (me). For a moment, I make sense of the Islamic system - cutting off the evil at the root rather than allowing it to spread.