Some people go to extraordinary lengths to stop colleagues stealing their food and milk from the office fridge.
Doncaster Council recently tweeted a picture - now since deleted - of a padlocked milk bottle found during a fridge clear-out.
We asked readers if they had had similar experiences and many said yes.
In fact, disappearing food and milk at work seems to be a widespread and niggling problem, especially when it comes to sugary food
Lauren, who works for an energy supplier, says: "Someone opened my can of Coca Cola, drank half and put it back in the fridge..."
Bethanie, who works in marketing, said: "I think the worst was when someone stole thank you chocolates from a client off someone's desk".
Some readers even admitted to taking treats - but by accident.
Software consultant Dan confessed: "I once took the last chocolate bar from Martyn... when I thought it had been left out for peeps. It was a careless Wispa."
But beyond padlocking your food - which seems rather extreme - what can you do to combat the office thieves?
Tony, who works at an electronics manufacturer, used laxatives to stop regular theft of his milk.
"I bought some liquid laxative and added it to my milk. Let's say he had an unforgettable day and I thought it was funny! He never touched my milk again."
For those of us who may think twice about dosing our colleagues with laxatives, one alternative could be a simple bluff.
K. Farrell, a commercial vehicle technician, says: "I had to laugh when someone I used to work with opened the fridge with everyone in the canteen and said 'Oh no! That had my medication in it! If any of you have drank my milk, you'd better phone your doctor.' Then just walked out.
"I found it hilarious because I knew he'd made it up. But there were some very worried people in there."
So why do people steal from office fridges?
Professor Cary Cooper of the Alliance Manchester Business School says in the main, milk going missing is down to people rationalising it as being communal.
"They don't see it as a crime. They see it as sharing," he says.
Taking people's lunch is different. "That's a bit nasty and probably a revenge attack", he says.
The thief could think: "I'm going to pay her back, take her lunch from her, and then say: 'I wonder who did that? That happened to me too. I wonder what the world is coming to?'"
He said people taking food for the thrill of it would be "very unusual".
"There's more exciting things to do," he says.
People get annoyed about food and milk being taken because they see it as a betrayal of trust, he adds.
Laying a trap
Another way of solving the problem of habitual petty lunch larceny is to lay a trap for the thief.
Theresa, who works in technology, was "enlisted... in a plot" to find out who was stealing food because her cubicle "was right next to the kitchenette".
Theresa says: "They put some cookies in a really loud crinkly bag. As soon as I heard the sound, I jumped up and ran around the corner... to see a fairly high ranking manager literally with his hand in the cookie jar! Actually there was no jar, but I will never forget the look on his face with the bag in his hand and cookie in his mouth."
Keep it close
One way of protecting your lunch is to keep it close.
Donna, who works in communications, seems to have had quite a serious number of lunches stolen. She says: "I bought my own mini-fridge and kept it under my desk."
Ian, who works in the pharmaceutical industry, takes a more low-tech, but still practical approach. He says: "I keep my food in my bag. Always have."
Sharing is caring
Of course, the other approach is to give up and accept your food as communal property.
Sulakshana, who works in public relations in Brazil, says: "Food is for sharing. I've seen my office friends sharing their home cooked lunchboxes with others. We even [swap] entire lunches - no need to steal food."
Lastly, one solution to the age-old problem of the office milk thief - make the milk free. At least to the employees.
Harry, who works as a solar energy consultant, says: "The simplest solution in my experience is for the employer to provide milk along with kitchen basics and accept the cost to the business. It really is worth it for the problems this avoids.
"This course of action also resolves the issue of having enough milk to make clients or visitors a cup of tea, saves space as everyone having their own milk takes up a ridiculous amount of the fridge, and lastly it avoids the horror of what happens when someone goes on holiday for two weeks and leaves their padlocked milk in the fridge."