A study published by the Office for National Statistics says that more than 480,000 people or one per cent of the UK?s adult population regard themselves as gay or lesbian while a further 245,000 or 0.5 percent say they are bisexual.
The data has been collected by the new Integrated Household Survey (IHS), which is the largest social report ever produced for the ONS.
The 450,000 individual respondents to the survey provided the biggest pool of UK social data after the national census, the statistics service said.
Another 0.5 per cent of adults said they are bisexual and a similar proportion described their sexuality as 'other'.
Just under 3 per cent of adults responded ?don?t know? or refused to answer the question. Fewer than one percent of respondents provided no response.
The highest proportion of adults who identified as gay, lesbian or bisexual were in London with the lowest found in Northern Ireland.
The IHS survey also incorporates questions relating to a wide variety of themes including religious affiliation, ethnicity and personal health.
The responses indicate that 71 percent of people in Great Britain identify with the Christian religion and 89 percent of people see themselves as belonging to the white ethnic group.
Across the UK, 80 percent of men and 78 percent of women reported said they regarded themselves as being in good health.