Before 1999, landlords were legally able to discriminate against tenants who kept animals and many letting advertisements simply stated 'no pets allowed'.

However, the introduction of the 'Unfair Terms in Consumer Contracts Regulations 1999' changed all that, because the Office of Fair Trading (OFT) decided it was unreasonable for such a generalised exclusion to be used.

The OFT determined that banning all pets meant access to rented accommodation could be denied because a tenant wanted to keep something as harmless as a goldfish - and that this was 'unfair'.

The OFT's guidance notes suggest that the landlord's consent for the tenant to keep pets must not be unreasonably withheld. The landlord should at least investigate whether the type of animal being proposed is suitable for the premises and whether it will be adequately supervised and cared for.

In practice, any clause that totally excludes pets is likely to be considered unenforceable, unless the landlord is able to prove the animal is a nuisance or health hazard or is causing damage to the fabric of the property or the landlord's supplied furnishings.