The so-called bedroom tax, which penalises tenants with spare rooms in social housing, would lead to a rise in people getting into debt and, ultimately, evictions, campaigners have warned.

But now advice agencies say tenants might be able to get around the tax because the law is unclear about what is classed as a bedroom.

They claim if tenants simply ensure spare rooms are not used as bedrooms, local authorities and housing associations can be challenged over any cuts in payments for housing benefit purposes.