LONDON – In the absence of responsible, comprehensive sex education, British students are taking lessons from porn, according to a new survey conducted by the National Union of Students.

When the organization asked 2,500 young adults to rate the sex education they received in school, two-thirds called the instruction “fair,” “poor” or “terrible.” One third indicated the courses they took provided at least some information they could use in practical, real-world situations.

In contrast, two-thirds of the same students indicated they found pornography provided more comprehensive — and comprehensible — sexual and relationship education.

A common complaint among the survey respondents was that the material taught in schools covered only scientific aspects like anatomy, contraception and puberty. More than half of students indicated relationship issues, including consent, were never discussed. Fewer than one-fifth received information about LGBT issues.

For many young people, porn fills the gap, a spokesperson for the NUS said — albeit in ways that are misunderstood or misrepresented by the media, religious groups and politicians.

Of the two-thirds of survey respondents who admitted to using pornography, 75 percent said they realize porn creates “unrealistic expectations.” However, lacking any other sources of information and instruction, seeking answers from porn is their only option.

The National Union of Students represents 600 student unions in England, Ireland, Scotland and Wales. The organization accounts for more than 95 percent of all higher-education student unions in the UK.