The headlines will tell you there are at least 85 sharia courts in Britain. There are definitely more and they have little to do with gavels and wigs and more to do with upholding the cultural and tribal status quo in communities.

Having been on the receiving end of sharia rulings – I must make it clear that sharia courts are often nothing of the sort and are more likely to be an imam at the end of a phone – I can speak about the arbitrary and random nature of these bodies. Contrary to popular belief, there is no central network, no supreme sharia judge, no sharia bar, no sharia AGM, no sharia ombudsman, no sharia HQ and no torts.

Sharia law isn't even written down and most Muslims will dip in and out of it when it suits them. They might be very particular about getting a sharia compliant mortgage but ignore the advice on archery and wrestling. Sharia courts/tribunals/whatever rarely have offices (although they may have websites) and they're certainly not in the habit of swapping notes for best practice. It's a bad comparison but the fluid, almost nebulous nature of sharia courts is like al-Qaeda without the violence and their ubiquity like a Domino's Pizza franchise. Any topping as long as it's halal.

Sharia is so abstract, yet so everyday, it's hard to ban, (sorry Denis) and you can't really adopt it either because much of it is at odds with British law and society in general (sorry Rowan). It tells Muslims how to live their lives in almost exhaustive detail. It spans everything from hair removal to jihad. To ban sharia law in the UK would involve banning imams – and we don't know how many of those there are – and to deprogramme Muslims to stop their default setting being Channel Sharia. You would also have to block websites and cut off access to phone lines and shut down mosques. There are plenty of people on this site who might like to see that happen. But I will leave that article to someone else.

When my father died, my mother decided that, although under British law she was entitled to everything, she wanted to settle things according to Islamic law so she could "die with a clear conscience". She asked my brother to call an imam. The imam said my brothers would get twice the share of my sister and I and so on. On learning that my father had a son by a previous marriage, the imam said my half brother must also have a share in my dad's estate. So, a man who is a stranger to us tells us that another man who is a stranger to us is entitled to a stake in our family home, where we have lived for 25 years and he has never set foot in.

The story about my half-brother is a complicated one and best left alone. But he – according to sharia – is entitled to more of a share than my sister and me. His claim would never stand up in a British court – he is not a citizen so I don't know how he would contest it – but in this case sharia law overrides British law. In another case, my friend's husband died several years ago. They were not married under British law, just Islamic law. Upon his death she was unable to prove they were married – he was the father of her children and they shared a home – and no imam or sharia body was able to come to her assistance. Sharia law, in this instance too, was found sorely lacking in common sense and justice. Had she married under civil law the ghastly practicalities that follow a death might have been less protracted and there might have been less anxiety about the security of her family. Had he been alive and had she chosen to divorce, her only remedy would have been a sharia divorce. But there would have been an almighty tussle over the kids, not to mention enormous family pressure from both sides to stay with him.

Ultimately, from my own experiences and from those of my friends, sharia is driven by the needs of a community rather than an individual. Whatever the protestations of its fans, this system of law does not favour women or local custom. While it is impossible to outlaw it, a better and more realistic solution would be to educate people about the advantages of British law, which, while it has its flaws, is more developed and grounded in reality and fairness.