The Human Rights Act 1998, put the European Convention on Human Rights into UK law.
Section 3 = legislation must be read and given effect in a way in which is compatible with the right within the European convention on Human Rights.
Only applies if someone's Human Rights are in breach within the case but this rule doesn't apply if no Human Rights are in breach.
Mendoza v Ghaidan - The Rent Act 1977 - if spouse died other half could take over the tenancy. The couple in this act wanted to find out whether same sex partners could take over the tenancy. House of Lords decided they couldnt but the Court of Appeal, overruled parliament using The Human Rights Act 1998, saying they need to comply with the European convention within the Human Rights which forbids discrimination on the ground of gender.