Women who have been pictured eating on the Tube and had their photos uploaded to a Facebook group have been urged to contact the British Transport Police.
Facebook page 'Women Who Eat on Tubes' invites people to upload pictures of strangers eating on the London Underground.
The page says it "is observational not judgemental. It doesn't intimidate nor bully.
"Subjects are embraced and cherished. We celebrate and encourage women eating food on tubes, we do not marginalise them. We always look for the story in the picture. We don't swear."
But according to the Evening Standard, Steve Burton at Transport for London said: "If someone doesn't want their photo taken it is obviously inappropriate to do so.
"If any customer has concerns about such behaviour, believing there may be a sinister motive, they are advised to speak to our staff or the British Transport Police."
It is not illegal to take photos of people on the Tube but privacy campaign Big Brother Watch has called for the law to be changed.
Deputy Director Emma Carr told The Daily Mail: "The laws protecting our privacy were written long before social media, camera phones and widespread broadband access.
"Cases like this should be dealt with proportionately, and people absolutely need to be able to seek redress if they do not wish to have their photograph on this kind of website.
"Unfortunately this is a problem that will get worse before it gets dealt with.
"It's obviously not realistic to expect social networks to police whether photographs have been taken with consent, but there is clearly a need to look at where people are creating forums to encourage and share photos taken.
"Equally banning camera phones isn't going to work, so we need to make sure that the law deters people taking photos of other people, especially if their intent is to publish them."