All schools should include a positive portrayal of same sex relationships in their sex education lessons, teachers declared today.

Delegates at the National Union of Teachers' annual conference in Harrogate backed the idea that sex education should be a compulsory part of the curriculum.

They warned that homophobic bullying was still rife in schools - and argued that a positive portrayal of same sex relations could counteract that.

Annette Pryce, for the union's executive, said the Coalition Government had promised to tackle homophobic five years ago but "five years later we still haven't seen any progress".

Michael Dance, from Redbridge, added: "In many schools homophobic bullying is still rife." As a result, pupils were self-harming and even contemplating suicide.

The motion called for all teachers to be given training in how to deal with homophobic, bi-phobic and transphobic issues.

It took a sideswipe at Education Secretary Nicky Morgan who did not vote in favour of gay marriage when legislation came before the House of Commons, saying the incoming government "should appoint an education secretary that supports LGBT (lesbian, gay, bisexual and transgender) rights and has a positive track record in supporting civil partnership and gay marriage".