A friend arrives at our house in what is not her car, which is curious, because she has a very reliable car. She drives a Toyota. It’s even possible I once said “buying a Toyota is a good idea”, because it’s much safer, if less interesting, advice than suggesting somebody buy a Cosworth BDR-engined Caterham Seven HPC. 

Anyway, Helen lives in south London and owns an Auris Hybrid, which will be enough information for many of you to know why she is now driving a rental Aygo. Recently, she parked her car for half an hour, came back, started it and was surprised to hear a noise like somebody had nicked the exhaust. 

They had. Catalytic converter theft has been a problem for a while and it’s a particular problem on second- and third-generation Priuses and second-gen Auris Hybrids.

The trouble is that prices for metals like rhodium, platinum and palladium are high and catalytic converters contain them all, making them expensive. 

Sometimes the stolen cats get stacked into containers and taken overseas to reclaim the metals. Toyota says sometimes the complete unit finds its way back underneath a car whose catalyst has been stolen or has worn out. And there are quite a lot of high-mileage, low-value hybrid Toyotas around the nation’s capital – as you’ll know, because black-cab drivers are quite cross about many of them. Removing the catalytic converter from a Prius or Auris with a grinder or pipe cutter is apparently not a long job. Helen’s Toyota dealer reckons it can take as little as 90 seconds.