The government has been forced into a climbdown over plans to make sex education compulsory for all pupils over 15.

Gay rights campaigners had welcomed the plans as they would have ensured that all pupils were taught about gay relationships, homophobic bullying and HIV.

But education secretary Ed Balls was forced to drop several parts of the legislation today in order to ensure it becomes law before the general election.

Mr Balls has already been accused of “watering down” the provisions to allow faith schools to teach about homosexuality in line with their “religious character”.

In February, groups such as the Accord Coalition accused him of performing a U-turn and introducing a “21st century Section 28″, which they argued would lead to more homophobic bullying.

Currently, parents have the right to withdraw their children from sex education up to the age of 19. The bill would have ensured that all children received at least one year of sex education lessons.

Other measures that have been removed include making parents sign good behaviour contracts with schools and a guarantee of one-to-one tuition for pupils who fall behind in English and maths.

Lisa Power of HIV and sexual health charity Terrence Higgins Trust called the climbdown “disgraceful” and claimed it could lead to more homophobic bullying.

“We will see the impact on young people who haven’t had decent sex and relationships education. The girl who gets pregnant because the only education she got was in the playground, the people who use the word ‘gay’ as an insult,” she said.

“This isn’t just about sex – it’s about relationships, it’s about bullying, it’s about a whole raft of things.”

Derek Munn, Stonewall’s public affairs director, said that the move was “regressive” step and that Stonewall would lobby the next government to address the concerns.

He said: “Taught well, PSHE – including sex and relationship education – empowers young people to make informed decisions about their personal wellbeing. No young person should be denied this. We’ll be calling on the next government to revisit this as a matter of urgency.”

Mr Balls has accused the Tories of putting young people at risk by opposing his plans.

He wrote to his Tory counterpart Michael Gove: “Our reforms would ensure that by reducing the age of parental opt-out to 15, all children receive at least one year of compulsory sex and relationship education.

“This is a very significant setback, which will deny many young people proper and balanced sex and relationships education.”

A Conservative Party spokesman said: “This bill would have meant a great new wave of bureaucracy swamping schools and it is good news that it has collapsed – teachers will breathe a sigh of relief. “