ONS figures show those saying they are heterosexual fell from 93.4% to 93.2% in 2017

The proportion of people identifying as heterosexual in the UK has continued to decrease, especially among younger people, according to figures from the Office for National Statistics.

Using data from the annual population survey it found that in 2017 93.2% of people – equating to about 49.2 million – said they were heterosexual, down from 93.4% the previous year and from 94.4% in 2012.

The proportion who self-identified as lesbian, gay or bisexual (LGB) remained unchanged from the previous year at 2%, or 1.1 million, but the proportion who ticked a box marked “other” increased from 0.5% to 0.6%. A further 4.1% said they did not know their sexuality, or refused to answer.

The ONS said there was no further breakdown of the “other” category, so no assumptions could be made about sexual orientation or gender identity of this group.

“It might also include people who responded other for different reasons, such as those who did not understand the terminology or who are against categorisation,” it said.

People aged 16 to 24 were more than twice as likely as the general population to identify as lesbian, gay or bisexual. The survey recorded that 4.2% of younger people said they were LGB.

The 16-24 age group also had the highest proportion of people recording their sexuality as other, at 0.9%, and the highest proportion either refusing to state their sexuality or saying they did not know, at 5.3%.

Nationally 2.3% of men, compared with 1.8% of women, identified as LGB. But in the youngest age group more women (4.7%) identified as LGB than men (3.7%). The ONS said the disparity was driven by a larger proportion of women identifying as bisexual in the younger age bracket.

Paul Twocock, director of campaigns, policy and research at Stonewall, suggested the survey was likely to have underestimated the scale of LGB population.

He said: “LGB people still aren’t able to be open about their sexual orientation with friends, family and colleagues. We know that only half of lesbian, gay and bi people (46%) feel able to be open about their sexual orientation to everyone in their family, and nearly one in five LGB people (18%) aren’t open about their identity with anyone at work.”

He added: “We’re pleased the government plan to include questions on sexual orientation and gender identity in the 2021 census, which will give an even more reliable indication of the size and location of the LGBT population in the UK.”

Regionally, Londoners were most likely to identify as LGB (2.6%), and people in the north-east and east of England were the least likely (1.5% in both regions). More people in the north-east (96.4%) claimed to be straight than anywhere else except Northern Ireland (97.1%).

Chris Ramsay, the chief executive of Sunderland Pride Group, which runs an annual festival as well as weekly drop-in sessions, said: “A lot of people round here are scared to come out. We do have a lot of people who come in here who don’t want to come out … a lot of younger people. Some don’t want their friends to know they are gay. It’s still rife up here, that sort of thing.”

He said hate crime was on the increase. “It did get better for a few years but it’s getting worse, I think because of lack of funds and lack of services out there to educate people and get people in the right direction. Run-of-the-mill people are not educated in LGBT things, it’s not the norm to them.”

Student cities such as Sunderland and Durham no longer have any dedicated gay bars. Ramsay, who DJs in Sunderland, said: “There’s nowhere for LGBT people to go out in Sunderland any more, so if they do go out they always get abuse. You see two lads kissing in a bar and they’ll get abuse. There’s no safe haven for them any more.”

He thought the statistics might reflect the fact that some LGB people chose to leave the north-east. “A lot of people round here do move to Leeds or Manchester to get away.”

Last month the ONS recommended adding new voluntary questions on sexual orientation and gender identity for people over 16 to the next national census, in 2021. It said these would “meet the needs for better-quality information on the lesbian, gay and bisexual population for monitoring and for supporting anti-discrimination duties under the Equality Act 2010”.