The proportion of the UK population aged 16 years and over identifying as heterosexual or straight decreased to 94.6% while the lesbian, gay or bisexual (LGB) population increased to 2.2%, Office for National Statistics figures show.
In 2018 over 53.0 million people identified as heterosexual or straight. This represents a continuation of the decrease seen since 2014, when 95.3% of the population identified themselves as heterosexual or straight.
Meanwhile, in 2018 there were an estimated 1.2 million people aged 16 years and over identifying as LGB.
Men (2.5%) were more likely to identify as LGB than women (2.0%) and younger people (aged 16 to 24 years) were most likely to identify as LGB.
Among English regions, people in London were most likely to identify as LGB (2.8%), with people in the North East the least likely (1.8%).
In 2018, the percentage of people who identified as lesbian, gay or bisexual (LGB) was similar for England (2.3%), Wales (2.4%) and Scotland (2.0%).
For Northern Ireland, the percentage of people identifying themselves as LGB in 2018 was 1.2%. The UK average in 2018 was 2.2%, which has increased from 1.6% in 2014.
The higher proportion of people identifying as LGB in London may be explained by the younger age structure of the population. The median age of the population in London was 35.3 years in 2018, compared with 41.8 years in the North East of England.
The East Midlands and West Midlands were the regions that saw the largest change in the proportion of people identifying as LGB over the last four years, with both increasing from 2014 to 2018 (from 1.2% to 2.2% and 1.3% to 2.3% respectively).
A statistician at the ONS said: “People in their late teens and early twenties are more likely to identify as lesbian, gay or bisexual (LGB) than older age groups.
“Meanwhile, more than two-thirds of the LGB population are single (never married or entered into a civil partnership). This reflects the younger age structure of this population, the changing attitudes of the general population to marriage and the fact that legal unions have only recently been available for same-sex couples.”