Having your bike stolen is an awful experience, especially if you've taken precautions to chain it up.
Sometimes locks aren't enough to stop a persistent thief, but nowadays they're considered the norm, thanks to the popularity of bicycle thefts in recent years.
The Metropolitan Police Service say that around 20,000 bikes are reported stolen in London each year, and advise, among other top tips, locking your bike with a D-lock as well as registering and marking your bike as a deterrent to thieves.
There are also alternative methods, which are highly inadvisable, but potentially hilarious as these YouTube clips show.
A pair of pranksters decided to attach electric shock apparatus to the frame of bikes, which they left abandoned around Los Angeles for unsuspecting thieves to pick up.
The results speak for themselves: