Flight passengers are being warned not to pack power banks or vapes in their hold luggage ahead of the busy summer holiday travel period beginning for parts of the UK.

The fire risk posed by lithium batteries is now the number one safety risk to aircraft, according to the aviation regulator, as the number of devices found in hold bags has nearly doubled in a year.

The Civil Aviation Authority (CAA) says the average person now takes four different lithium powered devices on a flight.

Ahead of the school summer holidays, which begin in Scotland first this week, people are being reminded to take devices in the cabin with them.

The batteries can store huge amounts of energy in a small space, and are now commonly used in lots of electrical items including laptops, vapes, power banks, mobile phones and smart watches.

They’re incredibly useful and versatile. But if the batteries overheat or are defective, a fire can result which spreads very quickly and is hard to control.

In 2024, 316 incidents of devices with lithium batteries detected in hold bags were reported to UK authorities. In 2025, that rose to 643.

Reports of devices overheating or malfunctioning also nearly doubled the same year, from 123 to 206.

Most of these issues occurred in the cabin where crew could deal with the situation, but the concern is that if this happens in the hold, the problem may not be discovered until it’s too late to control it.

The CAA says around two lithium battery incidents are now occurring each week.

Apart from the risk of fire, having to remove bags from the hold can cause delays.

Planes can even be diverted. Last month an EasyJet flight had to divert to Rome because it emerged a power bank had been packed in the hold.

In October, video was widely shared of flames belching from the overhead storage compartment of an Air China flight, reportedly caused by a lithium battery.

The CAA believes many passengers still aren’t aware of the rules.

Passengers are being reminded:

Tim Alderslade, Chief Executive of Airlines UK, says the risk of lithium battery incidents was a “growing challenge” as the number of electronic devices people use increases.

“Whilst pilots and cabin crew are trained to deal with any situation the best outcome is always prevention, which starts when passengers pack their bags,” he says.

Giuseppe Capanna, a product safety engineer at the campaigning charity Electrical Safety First, said lithium batteries carry enormous amounts of energy, which is handy for recharging devices.

However, it also means that when things go wrong, they can cause “ferocious” fires which are difficult to put out.

“When these products are packed in your baggage, there is no access to them. So if something goes wrong, they can cause a really devastating fire that can have real dangerous consequences,” he said.

While most devices with these batteries are safe, Capanna said it was “substandard versions” bought through third-party sellers that usually caused these problems.

“It is really important that we make sure that we only bring safe, tested products with us on holiday,” he added.

Additional reporting from Danielle Codd