From simple pranks to acts that cross the line into breaking the law, anonymous employees have shared what they have done to get their own back.

Real Business does not condone these acts of revenge of course. While some of the top ten stories are amusing, there is also a serious side to workplace revenge: for example where serious pranks can hit company profits or even cause injury to the victims.

“Petty acts of revenge can usually be laughed off,” says Mark Hall, spokesperson for Protecting.co.uk, which compiled the list. “But as soon as the prankster starts targeting customers, suppliers and competitors, your organisation could be letting itself in for costly legal action from which there is little defence.”

Here are the 10 best workplace revenge stories:

• “The cling film over the toilet seat thing is so last year. To get my own back on miserable colleagues, I fixed the light sensor in the loos to plunge the room into darkness after one minute. Just time enough to settle down on the toilet, I should imagine.”
• “I’m a manager. If my staff annoy me, I schedule a long meeting with loads of trivial points on the agenda, and then lie about having to be elsewhere after ten minutes. Guarantees at a good hour of peace and quiet at my desk.”
• “Always make sure there’s a huge wheelie bin parked in the boss’s personal parking space. Sends a message.”
• “I left a message on a colleague’s desk saying ‘Please phone Liz’. It was the number for Buckingham Palace.”
• “Garage mechanic here. Give us grief about your repair job, and we’ll change all the pre-sets on your car radio.”
• “I work in a shop. Got my own back on the boss for his petty penny-pinching and refusal to pay more than minimum wage by passing (ahem) special discounts on to customers.”
• “Horrible in retrospect. I got stiffed by a company on a huge business deal, so I set up meetings with them, pretending to be a new customer in Penzance. They’re based in Sheffield. On the day, got a load of panicked emails from the sales-team driving round Cornwall trying to find my offices. Pure joy.”
• “My boss took credit for a 350-page report I wrote and got a huge bonus. I complained and got shifted to the bad debts department. Was it wrong of me wipe all of his department’s computer files and get him suspended? Probably illegal.”
• “Nothing says revenge better than the contents of a packet of fish fingers concealed in the office of the colleague who had you disciplined for no reason at all.”
• “Former bus driver. Rude to me when you get on? I might not hear the bell when you’re trying to get off. Especially if it’s raining.”

Two wrongs do not make a right – and indeed some of these tales could end up with companies facing legal trouble or claims for unfair dismissal.

The best approach a company can take is to create an atmosphere and working conditions where employees are not driven to revenge.

“Pranks are fine within certain limits,” says Hall. “But wrecking livelihoods and insulting customers is just not worth it.”