More than 400 people in Doncaster are currently cheating on their partner, according to a new sex survey.
The study by Illicit Encounters, a website for married couples to enjoy affairs, reveals that Doncaster has 419 love cheats.
The so-called Infidelity Index reveals that Royston is the worst place in South Yorkshire for cheats - with a whopping 1,129 doing the dirty on their other half.
The ‘cleanest’ town is Rawmarsh with just 240 adulterers.
The shocking figures put Doncaster 124th nationally out of the UK's 140 most adulterous towns with Barnsley 77th and Rotherham 133rd.
IllicitEncounters.com, the UK’s leading dating website for married people, have created the Infidelity Index, revealing the amount of adulterers - and the most adulterous towns - across the United Kingdom.
IllicitEncounters.com compiled the figures based on the geographical data of its 1 million + members.
The overall standings saw High Wycombe crowned the most adulterous town in the UK, sporting the highest relative percentage of cheaters (2.12%). It was closely followed by Guildford and Aldershot, who came 2nd and 3rd respectively, with 2.05% and 2.03% of their population cheating.
"More and more people are signing up to the site every year,” spokesman Christian Grant said.
“The reason for the surge in subscriptions is that record numbers of married couples in South Yorkshire are living together unhappily because they simply cannot afford to divorce.
"Spiralling house prices and living costs have made it financially impossible for couples to set up two homes following a split, so they struggle on while seeking excitement elsewhere.
"The beauty of IllicitEncounters.com is that they can meet like-minded people in a discreet environment. Both parties are looking for fun but don't want to upset the applecart at home. They can have an affair with little risk of getting caught."