Consumers have been warned only to buy e-bikes and e-scooters from reputable retailers following a dramatic surge in house fires caused by unsafe batteries and chargers.

An “alarming spate” of fires has been attributed to non-compliant lithium-ion batteries used in the bikes and scooters, the Chartered Trading Standards Institute (CTSI) warned.

The number of fires caused by the batteries has surged by almost 150% over the past year, according to Freedom of Information data obtained by the insurer Zurich, while firefighters in London alone attended 88 fires caused by e-bikes last year – an increase of 80% on the 49 responded to in 2021.

The CTSI is urging businesses importing and selling e-scooters, e-bikes and conversion kits, which change a standard bike to an e-bike, to ensure that the products fully comply with product safety laws.

Consumers should only purchase devices from reputable retailers and check that they display a valid UKCA or CE mark.

Christine Heemskerk, CTSI lead officer for product safety, said: “Don’t buy online unless you’re really certain where a product is coming from.

“You also need to be very sure that you’re using the right charger for the right battery. There should be a charger supplied with the device you’ve purchased.”

Alonso Ercilla, Trading Standards manager at the London Borough of Islington, said: “For importers and retailers, getting this wrong could cost you an absolute fortune. Trading Standards can seize non-compliant devices and gain a forfeiture order so that we can safely dispose of them.

“We advise anyone selling these devices to get them tested to make sure they comply with product safety laws. When things go wrong, there are consequences. Businesses can be prosecuted and the public can be exposed to great risk of harm.”

London Fire Brigade assistant commissioner for fire safety Charlie Pugsley said: “There is a significant risk posed by the e-bikes which have been converted and we are predominantly seeing fires in ones which have been purchased from online marketplaces and batteries which have been sourced on the internet, which may not meet the correct safety standards.

“When these batteries and chargers fail, they do so with ferocity and because the fires develop so rapidly the situation can quickly become incredibly serious. These items are often stored in communal areas and corridors and can block people’s only means of escape.”

London’s Walking and Cycling Commissioner Will Norman said: “All privately owned e-scooters remain illegal in public places and on the road in London, but they are not illegal to purchase.

“It is vital that customers understand the potential consequences of riding e-scooters and those who do purchase the vehicles must be clear on how to charge them and their batteries safely. E-bike owners must also be aware of the fire safety risks which come with using converted e-bikes from unverified suppliers.

“The Mayor and I are determined to build a safer London for all. That is why I recently wrote to retailers with the Met Police imploring them to display information prominently in store and online to make customers aware that private e-scooters are illegal on public roads and to make it clear to customers that do purchase them how to charge vehicles and batteries safely.”

Lesley Rudd, chief executive of Electrical Safety First, said: “Our own investigations have found dangerous chargers for e-bikes freely available on online marketplaces, leaving shoppers at serious risk of a fire.

“The Government must better protect the public by regulating online marketplaces to force them to take reasonable steps to ensure that goods sold on their platform are safe.”