I have 3 children who are 8, 5 and 4 and they are sharing the same bedroom at the moment, the older two are girls and the youngest is a boy. I've been on the council waiting list for a 3 bedroomed house for over 4 years now but as far as they know it is okay for the children to be sharing a room. What is the legal age that opposite sex siblings cannot share a bedroom in England?

I do not believe there is a law. There was some discussion about this in the UK a while back and a general statute could not be found.

There may be a local law, however. Best to speak with a local solicitor or other legal professional.