OFFICES will be sizzling with sexual tension and unrequited love this Valentine's Day, according to a survey.

Nearly half of office workers admit that they have snogged a work colleague and nearly 17 per cent have taken their romances further by having sex in the office.

The most popular office location for a steamy session was the desk, followed by the manager's office and the toilets.

The survey of 3,000 workers by fish4jobs.co.uk, a popular recruitment website, also found that the boss is an object of lust.

One-third said that they have fancied their boss and one-quarter have fantasised about bedding him or her.

The survey also found that office affairs are rife, with one in five admitting to an adulterous relationship.

The survey also found that flirting is a part of everyday office life - nearly six out of ten people flirt with colleagues.

Sean Mahon, marketing director for fish4jobs.co.uk, said: "Given that we are now spending more time with our colleagues than with our family, it's hardly surprising that romance is blooming in offices nationwide."

Meanwhile firms could be planning to introduce "love contracts" to head off any problems caused by staff striking up relationships at work, the TUC has warned.

Officials said they feared some businesses were trying to copy their counterparts in the USA, where workers have to sign a contract agreeing to behave in a professional manner if they start dating a colleague.

TUC deputy general secretary Frances O'Grady said: "It's hardly surprising that relationships do start round the water cooler, after all we work longer hours than anyone else in Europe.

"Of course it is right to be careful and think through all the implications, but heavy-handed rules and blanket bans fail to understand human nature and may very well be illegal."

The TUC warned firms they could be in breach of the Human Rights Act if they tried to persuade staff to sign an agreement that restricted workplace relationships.