Censorship via British Libel Law
British libel law is very slanted towards the complainer and some oil-rich Muslims have realized that. So if a book is published which is critical of Islam, they sue in British courts. British publishers don't have the money to take them on so the publisher agrees to withdraw and pulp the book. Books that expose some very shady characters in the world of Jihad are thus no longer available. There is a post here that goes into details. As always, the internet is thwarting the censors, however.