Ten thousand schoolchildren should march on Westminster in protest at a House of Lords’ rejection of plans to make sex and relationships education mandatory, says a leading gender and culture academic.

Emma Renold, professor of childhood studies at Cardiff University, is calling for direct action by those most affected by the Lords’ decision.

On Tuesday this week, 209 Lords voted against the addition of an amendment to the Children and Families Bill, which would have made sex and relationships education (SRE) compulsory in all state-funded schools. Only 142 Lords voted in favour of the Bill.

Jules Hillier, of the sexual-health advisory service Brook, said: “We’re told by young people that the information they get in schools at the moment is not relevant to their lives. It’s too little, too late and too biological.

“If you anchor all your SRE in science, you’re missing out a lot of the advice that young people need to have healthy, happy lives.”

Professor Renold recently conducted research into pre-teen children’s experience of sexism and sexual harassment. Many children talked about feeling pressured to find a boyfriend or girlfriend.

“There’s a big disconnect between the House of Lords and children’s lives,” Professor Renold said. “I’m definitely going to ask kids what they want to do about this. How do you want to lobby government and make your voice heard?

“Sometimes a ‘no’ vote energises people. It will whip up their passions. I think there’s enough energy around. It’s just about getting organised enough.”

As well as a 10,000-child march, she suggests that schoolchildren send politicians accounts of their own experiences of sexism and sexual harassment.

Andy Phippen, professor of social responsibility at Plymouth University, would also like to see pupils taking direct action. “Some sort of action is generally more useful than producing another piece of research,” he said.

Professor Phippen regularly delivers sex-education lessons in schools. Many of the girls he teaches to do not realise that they are entitled to say “no”, when their boyfriends ask them to text them naked or compromising photographs.

“I’d love to take a government minister and sit them in a room with young people,” he said. “I’d say, ‘Why don’t you listen to what they need?’ I’m sure it’d be very eye-opening.”

Ms Hillier agreed, and she pointed out that Brook speaks to around 300,000 schoolchildren each year. “Putting policymakers in the classroom is a good idea,” she said. “I don’t think there’s an education minister anywhere who wouldn’t benefit from hearing what young people have to say.

“Always, policymakers could do with a little more exposure to the people their policies affect.”