Would you say the following clause in a tenancy (AST) does not permit a tenant to rent a room (or even the whole property) out during the Olympics? I think it does not allow it.
'Not to assign, or sublet, part with possession of the property, to let any other person live at the property'
Many ASTs will have a clause such as this in them but how do you enforce it? The difficulty is that if the tenant knows he/she is breaking the agreement this way then they very probably wont allow you access for an inspection where you'd be able to verify it.