Less than a fifth of all university students discussed LGBT issues in their Sex and Relationships Education (SRE), a survey by the National Union of Students (NUS) reveals.

Gaps in teaching were uncovered, with three-quarters (75%) saying they found out about sex and relationships through friends.

According to respondents, consent was never touched upon in lessons for two-thirds of them, while relationships were covered for less than half.

The NUS said more than a third did not rate their SRE positively on equality and diversity, with less than a fifth saying they were taught about LGBT relationships.

More than half felt the issues they needed to know about were not taught, with only a third feeling they could practically apply their SRE to their real life.

Students agreed that porn was now a standard part of a young person’s life, but three-quarters felt it provided “unrealistic expectations”.

The union, which surveyed 2,500 students, said the results showed an urgent need for statutory SRE in all schools.

The NUS is calling for the measure to be introduced as part of its New Deal general election manifesto.

NUS Vice President Colum McGuire said: “SRE is failing millions. It is not currently compulsory for schools to teach young people about sexual consent and healthy relationships, and LGBT relationships.

“Ignoring all of this is just completely unrealistic. It will never go away – its life. Sexual consent, learning about equal and respectful relationships and gender stereotypes must be alien to this government as they don’t rate them high on the list to educate young people on.

“The government has a responsibility to provide a safe and reliable environment to explore sex and relationships. This is about providing the knowledge young people need in order to make good decisions for themselves.”

A Department for Education spokesman said: “Good quality relationship education is an important part of preparing young people for life in modern Britain, and our statutory guidance makes clear that it must be taught in an age appropriate way.

“Sex and relationship education is compulsory in all maintained secondary schools and many primary schools also teach it in an age appropriate manner.

“We also expect academies and free schools to deliver relationship education as part of their provision of a broad and balanced curriculum.

“We have set up a new expert subject group on personal, social and health education (PSHE) to support teachers, made up of leading professionals in the field, and will clarify the key areas on which teachers most need further support and produce new resources where necessary.”

The Education Select Committee will publish its findings on SRE in schools imminently, with the Conservatives yet to announce their position. Both Labour and the Liberal Democrats Labour are committed to introducing compulsory SRE.

Statutory status would allow SRE to be treated as other subjects – with teachers getting enhanced training, and enough time being allocated in school time-tables for the subject to address real life issues including – respectful relationships consent and LGBT.