My suggestion would be to get a copy of a standard lease and read through the clauses. There will be clauses that deal with what happens if the tenant damages the property ( there may be a limit on the damage repayment by the council) and what happens if the council tenant leaves the property as regards rent ( among others).
I have seen situations where the house owner finds themselves having to repair a badly damaged house, that a tenant has left in that state, the council paying only a limited sum, but the council won't put in a new tenant until the place is fully repaired and after notice limits in the lease etc. Leases will vary from council to council. Just be sure that you can deal with these problems if they occur and be aware that it can happen.