Quadruple? Because of demographics? Because criminals are living longer and are more spry?
Not quite. According to a leading think tank it's all because of European legislation (no surprise there) which forced governments to make shops and banks wheelchair friendly. Said one expert, "With ramp access to most shops and banks it's an open invitation to the less mobile criminal."
In Munich, a man in his 70s has held up nine banks and stores with a pistol and a walking stick.
In Berlin, a 70-year-old grandmother was recently jailed for robbing a bank of £6,000 with a toy gun.
Of course there is another explanation for the rising Third Age prison population that the think tank may have overlooked. Some of the ageing criminals are just not that good. And tend to be easier to catch.
Take, for example, the 75 year-old man who walked into a bank in Hamburg, pulled out his gun ... then forgot what he'd came in for.
Currently there are 50 inmates at the £5 million Third Age jail at Singen, near the Swiss border. Each cell is designed for the use of walking frames and wheelchairs. And instead of tobacco being the common currency of the cellblocks, it is arthritis medication and constipation pills. And, from what I've heard, 'pretty' sixty-year olds.