Every year we hold a summer party to thank all our staff for their hard work.  This year was no exception.  We held a party at work for all our employees, providing food, alcohol and entertainment.  During the party, it was noted on several occasions that one employee was taking a can of beer and disappearing.  It turned out that the employee was hiding the cans of beer under his sleeping bag in his lorry.  The employee is already on a written warning. 

Is this theft ?