Parents should have to physically go to schools and take their children out of sex and relationship lessons if they do not want them to take part in the classes, Peter Tatchell has suggested.

The campaigner argued that such a move would retain mums and dads’ right to withdraw youngsters from the subject, but ensure that only those that felt very strongly used the option.

Mr Tatchell also said that relationships education, including LGBT education, should begin from the start of primary school.

Speaking at an education conference held at Brighton College, Mr Tatchell, said: “I don’t believe that parents should have the right to withdraw their children from RSE, no more than they should have the right to pull their kids out of maths, history or science.

“RSE is about protecting children from sexual ill health and harm. Every parent should want that for their child.

“RSE is not about endorsing early sex or encouraging young people to have sex, we all know it’s best if they delay.

“But what it is trying to say is if young people do have sex, schools should give them the information they need to have sex safely and responsibly. To protect themselves and their partners.”

He added: “But if the Government is going to keep the option of parental opt-out from RSE, which is what I suspect they will decide, I think it should stipulate that parents have to come to the school and physically take their child out of each lesson.

“So just writing a note, that’s not good enough. This policy would maintain the parental right to withdraw their sons or daughters, but would ensure that only parents who feel really strongly avail themselves of the option.”

Under legislation passed last year, relationships education is now compulsory in all primary schools, while sex and relationships education is compulsory in secondaries.

As part of the move, guidance on the subject is being updated, amid concerns that the current advice is out of date and fails to address modern day issues such as cyber-bullying, sexting and online safety.

Speaking to reporters after the conference, Mr Tatchell said: “Relationships education should begin from the first year of primary school, focusing on love and commitment, not about sex.

“That should come later as kids are approaching puberty and need to know about the bodily changes that they will experience.”

Mr Tatchell said he was aware of a couple of secondary schools that have trialled policies requiring parents to physically take children out of RSE classes.

In one case, around 25%-35% parents had said in writing that they did not want their children to take part, but when the new policy was introduced, this went down to around 2%.

“The school had previously had a policy where there parents sent a note saying ‘I don’t want my child to receive these lessons’ and that was adequate, but then they introduced the policy where you have to come in and take your child out, saying ‘we accept your objections but you have to come in and take your child out of the lesson’.

“It maintains the principle of the parents’ right to withdraw their child, but they have to make a bit of an effort.”