More than a thousand people have given their support for a Facebook campaign aiming to place a ban on billboards which advertise themselves as a website for finding affairs.
Creator Jon Kuhrt is urging followers to write to the Advertising Standards Authority (ASA) to prohibit maritalaffair.co.uk, which calls itself as a "dating arena for those looking for adult dating and extramarital relations", from advertising publicly.
"When you think of the trauma and suffering caused to individuals and communities by the damage of affairs and the breakdown of relationships they cause I can't think of anything more irresponsible that could be advertised," Sky News quoted him as saying.
"The site is completely without any scruples other than making money - they are feeding on people's weaknesses and helping them to lie and ruin their own as well as their partners, and their families and children's lives.
"Sites like these will always exist but we do not have to tolerate their advertising in public places," he added.
A spokeswoman for ASA said the complaint about the Merton billboard had been turned down on the basis that the ad would not cause "serious or widespread offence".