A coalition of leftwing councils has agreed to defy new rules around single-sex spaces on the grounds that they are “harmful to the rights of trans people”.

On Wednesday, a new Equality and Human Rights Commission (ECHR) code of practice stating that sex refers to biological sex came into force. The guidance states that public bodies should operate single-sex spaces on the basis of biological sex – meaning trans people should only access the service corresponding to their gender assigned at birth or use gender neutral facilities.

The leaders of six London councils – Hackney, Haringey, Lambeth, Lewisham, Southwark and Waltham Forest – have now said in a letter to women and equalities minister Bridget Phillipson that they will not enforce the policy.