HR policies on workplace romances may need to be revisited as nearly 40 per cent of staff admitted to having a relationship with a colleague at some point in their career.

The survey of more than 7,700 full-time workers, from dating website Illicit Encounters.com, revealed that co-worker liaisons are common in the UK.

Employers should take note as office relationships bring with them the potential for costly tribunal claims of discrimination, sexual harassment and unfair dismissal.

While 38 per cent of survey respondents said they had dated a colleague, 17 per cent admitted they had done it more than twice.

In addition to tribunal claims, office dalliances can have a detrimental effect on staff productivity, the research suggests. For example, when love between colleagues in a small office turns sour, one member of staff may have to leave the organisation, while in larger firms it can mean costly and time consuming staff transfers.

Mike Taylor, head of the press team at IllicitEncounters.com, revealed: “One of the most rampant industries for inter-office relationships is the financial sector with 45 per cent admitting they have partaken in an office-based tryst.”

Perhaps unsurprisingly, the website, which focuses on matching married people who want to have an extra-marital affair, said it has a large number of members who have decided to cheat online as a result of the negative effects such a relationship would have at work.