"Homophobia is the last bastion of the bully," a teachers' union conference was told.

Delegate Tony Fenwick warned the National Union of Teachers' annual conference in Harrogate that the failure of the government to abolish Section 28 allowed a climate of prejudice against gay pupils and teachers to continue.

The conference voted by a large majority to pressure the government to increase its efforts to remove Section 28, which bans local authorities from promoting homosexuality.

Section 28 - of the Local Government Act 1986 - does not apply directly to schools.

But delegate John Burns said it cast a long, symbolic shadow - giving the impression to teachers that they could not be seen to approve of gay relationships.

Suicide

Mr Burns said that even in former grant-maintained schools, which were not even under local authority control, the threat of Section 28 had allowed homophobic bullying of pupils and teachers to continue.

The lack of support that gay pupils could expect from teachers, and the likelihood of bullying, had pushed many young gay people to attempt suicide, he said.

The isolation of gay pupils was emphasised by another delegate, Max Hyde, a teacher at Trinity School, Leamington Spa.

She said she had taught one teenager throughout GCSE and A-level before "haltingly and with trust in me, he explained that he had come to realise he was gay.

"He told how he had struggled with himself before coming out to me.

"I asked him why he had struggled alone for so long, when he knew what my reaction would be.

Bullying 'widespread'

"He said he had been afraid that in talking this over with me, he would put me in difficulties because of Section 28."

Bullying of gay pupils was still widespread, said Helen Currie.

This was not only a problem for the victims, it had a wider impact on the bullied child's family, friends, siblings and teachers.

"Ignoring bullying sends a message and Section 28 allows teachers to turn a blind eye," she told the conference.

A spokesman for the prime minister said the government still intended to repeal Section 28.

It was still hoping the House of Commons would overturn a Lords amendment scuppering repeal, after which the Bill would return to the Lords.