it's a genuine concern
for AST tenants (which is the vast majority of renters these days). worst case scenario would be that you'd have to vacate on little notice, though. for instance, i allowed today's tenants 28 days to find a new home.

if you want to avoid it, the 2 things to check carefully are: (i) has the landlord got consent to the letting from his mortgagee - if the mortgagee consents, it is bound by your tenancy; if not, the tenancy is in breach of the mortgage and so the tenant is no more than a trespasser as against the mortgagee - and (ii) is your deposit being held in a proper tenant's deposit scheme.

*helps*
( rachelswipe with a fork, Wed 17 Sep 2008, 15:38, Reply)