Gadgets that can be used to steal vehicles in a matter of seconds are being sold online for as little as £100.
Other items such as lock picks are also available to buy online.
The web retailers have come under attack from a crime commissioner who accused them of being “irresponsible” and said they should be taken offline.
Police chiefs say car theft, which has almost doubled in some areas in the country, has become “child’s play”. More than 86,000 cars were stolen in 2016 – 30 per cent more than in 2013.
Car theft had been in decline following the introduction of immobilisers, alarm systems and tracking devices. But new electronic gadgets has helped thieves to outsmart manufacturers and police, a Daily Mail investigation found.
Two main methods of car theft deploy devices available to buy online. The first type “relays” a signal from the keys inside the owner’s home to their vehicle outside. This opens the car’s doors and allows the criminals to make off with the vehicle.
Offenders have been caught on CCTV strolling up driveways, holding the devices against the owner’s front door and keylessly stealing their vehicle.
These relay devices are not on Amazon or eBay, but are sold on internet sites which can be found via Google searches.
The second method is a simple technique. It involves forcing entry to the car and using a programming device that tells the vehicle’s computer to trust a blank key.
David Jamieson, police and crime commissioner of the West Midlands, where car theft has soared by 80 per cent, criticised Amazon for selling programming devices
“We have a problem”, he said. “We are back to the bad old days. In the last two years car theft has been going through the roof and showing no signs of getting smaller.
“Somebody could have bought a gizmo, ordered it last night, have it delivered this morning and be stealing your car with it today.
“I’m saying to those companies these devices shouldn’t be openly on the market for sale. I have written to both eBay and Amazon asking them to remove the sale of these devices off their websites.
“EBay did tell me that they would take them off, however we found that they were all still on the website the following morning. I am challenging those people who are providing these pieces of equipment as to why they are still providing them.
“The fact they have yet to respond or take them down means they’re helping criminals – and it’s irresponsible of them to do so.”
Key programmers have been part of the car thief’s toolkit for a decade – but experts say their widespread availability and low cost has contributed to their increased use in the past couple of years.
Anthony Stansfeld, police and crime commissioner for Thames Valley, also demanded action.
He said: “This is a serious problem which needs to be sorted out by the car manufacturers.”
A spokesman for eBay said it had a policy against selling lock-picking devices, including key programmers.
He said: “We will continue to remove them, they are prohibited on our site. Thanks for bringing this to our attention.”
Amazon declined to comment.
A Home Office spokesman said it had “no plans to introduce new regulations in this area because as with all calls for a change in the law, there needs to be a strong evidence base”.
He added: “There is only limited, anecdotal evidence pointing to the use of key programmers and relay attack devices in vehicle-related theft.”