This information is kindly supplied by ARMA:
This advice note summarises some of the main health & safety regulations that apply to blocks of flats. This includes houses that have been converted into flats.
The duty to comply with health & safety regulations falls on the landlord or person responsible for managing the building. That could be a managing agent, a Residents' Management Company (RMC) or a Right to Manage Company (RTM).
Health & safety should never be ignored or dismissed simply because it costs money. The cost of failing to comply if there's an accident or injury could be far greater.