The council’s trading standards team is warning families of young children not to buy the illegal seats, which are imported from China and fail all UK safety standards.
Crash testing done by Britax shows the seats rip apart on impact at 30mph, catapulting a dummy the size of a three-year-old through the front of the car.
After following up an initial complaint about a Surrey sale, the county council has so far got around a dozen seats taken off the market and worked with online giants eBay and Amazon to remove over 100 more.
However, other foreign websites are still flouting UK law and selling the seats online to British customers, and the council has alerted the Department for Business, Innovation & Skills to the problem.
Helyn Clack, Surrey County Council’s Cabinet Member for Community Services, said: “Our priority is protecting Surrey families from these killer car seats, which tear apart so easily.
“We’ll continue to track and seize these deadly car seats, but our operation in England is just the tip of the iceberg as global online sales are our biggest problem.”
She added: “The crash test kindly carried out by Britax shows this car seat would cause horrific injuries at just 30mph, so tell us urgently if you’ve seen one and we’ll take action.”
The illegal car seats have no maker’s label. The council advises parents to buy a car seat that is new, made by an established company and, ideally, professionally fitted.
To report a car seat, contact Surrey County Council’s trading standards department on 03454 040506 (9am-5pm weekdays).