While it was the subject of some controversy when it was first published and adapted for film, it has never been officially banned in England (or any other country, for that matter).
It's important to note:
* The book was banned in certain libraries for a period of time.
* There were calls for a ban from certain groups who objected to its content.
* The film adaptation was banned in the UK for a period of time but is now readily available.
However, the book itself is still available for purchase and can be found in libraries across England.