Yes they are. Buiding Regulations specifies the 3 metre rule, as you say. Its within Part J document on Fire Safety. Phone your Building Control Officer at the local council. (This is nothing to do with the Planning Permission people - its a different group that assures buildings are constructed safely).
The Part J document says enforcement is through the HSE or its agents. I'm not sure whether BCO act as an agent for the HSE in this situation - but the general principle is that enforcement is through a prohibition notice if there is a serious failur to comply with BC regs.