Freedom of Information data obtained by Which? from 25 of the UK’s 45 police forces shows that between 2019 and 2020, catalytic converter thefts rose by 104 per cent on average amid a spike in the value of precious metals.

A single scrap catalytic converter currently fetches as much as £400 leading to organised gangs targeting tens of cars each day, Which? said.

According to the data, older hybrids, such as the previous generation of the Toyota Prius and Auris, and the Honda Jazz hybrid models are particularly at risk due to their higher concentration of precious metals.

A removed catalytic converter will render a car unroadworthy, so as well as producing higher levels of emissions, it will be illegal to drive.

Some victims said their car insurance premiums rose after reporting a stolen catalytic converter, while others struggled to find further insurance cover.

Harry Rose, magazine editor of Which?, said: “Catalytic converter thefts can leave victims with pricey repair bills, rising premiums or even complete write offs, so it’s concerning to see such a huge spike in these crimes across the country.

“To minimise the chance of your car being targeted you should consider installing traceable marking tools and a Catloc on your converter or park in an area covered by CCTV – these steps could help to identify or deter thieves.

How to protect your catalytic converter

Smart Water or similar forensic-marking tools making stolen catalytic converters traceable can deter criminals and are a strong tool in police investigations.

Fitting a ‘Catloc’ or similar device (costing around £200) will make removal more difficult.

If your parking spot is covered by CCTV, you increase the chance of deterring thieves and of police action being taken.