I didn't quite know whether I was writing for the non-Muslim or the Muslim, and at the end of the day I'm writing, I hope, for people who are interested, whatever their faith. Even if they don't have any faith. As a barrister I had certain advantages - I could think like a lawyer and I knew how all the laws were fitted together and all the rest of it. One of the things I realized pretty early on while I was writing book about Shari'a was that that was as much a hinderance as it was a help because the Shari'a isn't just a system of rules.

Whereas a man is entitled to marry three more times and that fosters great abuse, even scholars accept that. So certainly since the 1980s Shari'a courts have been established and they allow for women to go to them and they basically grant them annulment. It's not a civil divorce, they don't have the right to grant alimony or maintenance or custody.

The first rules about Islamic law weren't even written down for a century and a half after the Prophet's death, and it was another five centuries, half a millennium, before they assumed anything like a definitive form. So there have always been huge arguments over what Islamic law actually requires. There are four main schools of law in Sunni thought and there's a separate school of law in Shia thought, so these arguments do take place.

I think it's important to understand Shari'a to be rooted in history - what we know about the history and what we don't know about the history. So then, if people want to argue, at least they're arguing from the same point and we know what we know, and we know what we don't know.

One of things that surprised me when I was in Iran was to find out that the country finances seven times as many sex change operations as the entire European Union. And the reason for that is because Ayatollah Khomeini himself, in the early 1960s, in the same time that he was developing this other idea of an Islamic state, also hit upon the idea that if a person is born into the wrong sex, it was entirely proper for them to change sex.

One of the big problems in this field is that there's so much mystification that surrounds talk of the Shari'a, whether its saying that Islam is all about peace or whether its people saying that Islam is all about Jihad and all about suicide bombs. People will make statements which don't seem to be backed up by any sort of historical context.

I didn't quite know whether I was writing for the non-Muslim or the Muslim, and at the end of the day I'm writing, I hope, for people who are interested, whatever their faith. Even if they don't have any faith. As a barrister I had certain advantages - I could think like a lawyer and I knew how all the laws were fitted together and all the rest of it. One of the things I realized pretty early on while I was writing book about Shari'a was that that was as much a hinderance as it was a help because the Shari'a isn't just a system of rules.