‘Recently we had a guy off sick for three to four months who we found selling cars at the local BMW dealer. And we had another guy off sick with a bad back who we heard was working on a farm,” says Dave Smith (not his real name), an employee relations manager for a large manufacturing company.

“Somebody from HR would have to physically go and observe them to catch them at it but that puts you in a difficult position – you’re not well received, you’re on their patch, and it can be quite intimidating.”