We are currently constructing an extension onto the rear of a council property with the tenant still in residence and left him with access  to the rear via a small walkway to the rear door as a fire escape. But due now the works are getting further on we now need to remove that access to the rear door because we need to carry out works in that part of the kitchen. But the tenant is being obstructive and keeps stating that the law states that he needs access to the rear in case there is a fire at the front door but due to the type of work being carried out ie excavations we has a company have a duty of care to protect the tenant from injuring himself on the construction site and want to prevent him from accessing the rear are we within our rights and is there a regulation that covers this type of event as we have looked over CDM and Fire Regs and there seems to be a void in this  matter . Any help in resolving this matter is greatly appreciated

Without knowing the layout of the premises it is impossible to give a definitive answer and if The Regulatory Reform (Fire Safety) Order 2005 applies. It does not apply to domestic premises other than the common areas of flats. If you apply means of escape (MoE) principles to most houses they would not need an alternative MoE and only escape through the front door would be acceptable. You need to study Approved Document Part B Fire Safety which would help you to decide what is acceptable.