Sex and relationships education (RSE) is to be made compulsory in all schools in England, the government has announced.

The Education Secretary, Justine Greening, says that all children from the age of four will be taught about safe and healthy relationships and children in secondary schools will be given age-appropriate lessons about sex.

The move follows months of campaigning from MPs and charity groups who successfully argued that the current curriculum is years out of date and does not reflect the dangers faced by young people today.

MPs across all the major political parties had lobbied for such change, calling the previous guidance published in 2000 hopelessly inadequate for a modern-day world in which children are exposed to pornography, online grooming and abuse at the touch of a button and at an increasingly young age.

Politicians and charities have welcomed the radical overhaul of sex and relationship education but some secular campaigners expressed concern about the opt-outs that could be available for faith schools, saying the government needed to ensure some pupils were not left vulnerable.

Prior to the announcement, the national curriculum stated that SRE is compulsory from age 11 onwards. It involved teaching children about reproduction, sexuality and sexual health. It didn’t promote early sexual activity or any sexual orientation. However, only some parts of sex and relationship education were compulsory - these are part of the national curriculum for science. Parents were also able to withdraw their children from all other parts of sex and relationship education if they wanted to.

However, the Government is now pledging to bring in new "Relationship and Sex Education" to every primary and secondary school in England, including academies, independents and (most controversially) even religious free schools.

RSE must be delivered "in a sensitive manner which is appropriate to the age and understanding of pupils and the ethos of the school".