Our borough has pretty high rates for it (apparently - it's an area the missus covers a bit in her work), and it's completely different to circumcision in pretty much every way. Firstly, circumcisions are done by doctors, so are usually conducted in a safe and sterile environment. FGM, by contrast, are usually done by members of the family, which presents not only difficulties in terms of safety, but which girl is going to shop in their mother/grandmother for butchering them? Secondly, circumcisions are largely done for hygiene purposes and don't hinder the sexual performance or enjoyment of the individual. FGM is done out of the daft belief that it will make women more faithful to their husband, and not only hugely hinders their sexual enjoyment, but results in a lifetime of pain (you can see women that have had it done as they walk in a unique way due to the pain apparently). So FGM is more of a control thing by men over women, and this is compounded by many religious leaders promoting it as something that 'good' girls should have done, to the extent that any female who doesn't have it done can be ostracised from their community.
Several members of my wife's team in the NHS have had the procedure, and is truly gruesome. Given the complexities involved in actually identifying who has performed the activity, I don't know if even this new legislation would make 'that' much difference, but it surely can't do any harm either, especially when coupled with continued efforts at education.