There are over 1,000 people having an affair in Bromley, according to statistics.
The UK Infidelity Index, compiled by website Illicit Encounters, claims 1,151 of the borough's married residents are playing away.
Said to be the country's "largest and longest running dating site for married people", Illicit Encounters provides a platform for "a little romance" outside current relationships.
It states on its homepage it has not far from a million genuine users - suggesting many across the country enjoy borrowing some sugar from neighbours.
The data, which analyses towns with a population of over 50,000, also states neighbouring Beckenham harbours 623 unfaithful types, while Orpington has 434.
However, the towns fall shy of being the most prolific, with Maidenhead in Berkshire said to be the top spot for affairs. Nearby Gravesend was ranked at number six.