Looking for an online bargain? Beware of exploding batteries, dangerous toys, even socks that can burn you …

Many items sold through online marketplaces don't meet safety regulations. Then there are the counterfeits. Why is the law so powerless - and how can you protect yourself?

In a bedroom in Highgate, north London, a delivery courier plugged his ebike into a mains socket to charge it. The lithium battery began to overheat and burst into flames, setting fire to surrounding furniture. The man tried desperately to put out the fire and sustained serious burns before the firefighters arrived. The London fire brigade concluded that the blaze was caused by a charging lead bought online a few days before.

Lithium battery fires are occurring in the UK at a rate of at least six a week, often as a result of faulty batteries and chargers bought online. Self-employed delivery couriers, for example, may look to speed up their delivery times by using cheap parts to convert their pedal cycles into ebikes. They unwittingly buy unsafe goods from third-party sellers on online platforms such as Amazon Marketplace, eBay, Facebook Marketplace and AliExpress. But if just one cell inside a battery overheats, the high temperature can spread uncontrollably to others, causing rapid and devastating fires. These accidents happen due to a loophole in the law. According to Ian Mearns, the Labour MP for Gateshead, mainland Britain risks becoming almost a wild west, with unsafe products being peddled to unwitting consumers". The main area of concern is electrical goods.