The next UK census should include new questions on the armed forces community, the Government has been told.
Little is known about the exact numbers, location and needs of serving personnel, veterans and their families - estimated to number between 6.5 million and 6.7 million, according to the Royal British Legion.
The organisation is now calling for the community to be recorded in the next census, which will be carried out in 2021.
To mark the launch of the campaign - called Count Them In - four veterans have been painted into their surroundings to highlight their "invisibility" in current census data.
The pictures show them hidden at the Houses of Parliament, a library in Manchester, a cafe in Plymouth and a rugby ground in Cardiff.
Chris Simpkins, director-general of the Legion, said: "As a nation we promise to provide lifelong care and support for those who serve our country, yet we currently know more about the UK's 'Jedi Knight' population than we do about our own armed forces community.
"By adding questions to the 2021 UK census we can help public bodies and charities to deliver the best services they can for our armed forces community where they are needed most.
"It's time to make the next census count for our armed forces community. We count on them, let's count them in."