Most people wouldn’t think twice about where they leave their mobile phone before drifting off to sleep. However, with yet another heatwave sweeping across the UK, fire safety experts are urging households to steer clear of one all-too-common charging blunder.

It’s tempting to place a phone on the bed while it’s charging, or even tuck it under a pillow to keep it close at hand. This can trap heat, however, creating an unnecessary fire hazard right at the heart of your home. This risk becomes even greater during spells of hot weather, particularly when bedroom temperatures remain well above 25C long into the evening.

According to Electrical Safety First, such conditions mean a phone battery has far less opportunity to cool down naturally while charging, especially when buried beneath a duvet or pillow.

The charity advises that phones, tablets and laptops should always be charged on a hard, flat surface where heat can disperse freely. It cautions against charging devices on beds, sofas or other soft furnishings, as these restrict airflow and are highly combustible.

Meanwhile, the London Fire Brigade has also repeatedly warned against charging phones under pillows or duvets. It states that bedding can trap heat around lithium-ion batteries and chargers, significantly raising the risk of overheating should a battery or charging cable develop a fault.

The vast majority of modern smartphones are fitted with lithium-ion batteries, which naturally generate heat during charging. While these devices are built with numerous safety mechanisms, damaged batteries, counterfeit chargers or inadequate ventilation can considerably heighten the risk of overheating.

Rather than charging a phone on the bed, experts strongly recommend placing it on a bedside cabinet, desk or another firm, non-flammable surface that allows for adequate airflow.

They further advise using the manufacturer’s original charger wherever possible, and unplugging devices once fully charged rather than leaving them connected throughout the night.

Should a phone become unusually hot, begin to swell or emit a strange odour while charging, it should be carefully disconnected and not used again until it has been checked.

While battery fires are still relatively rare, experts warn that avoiding seemingly harmless habits — such as charging devices beneath bedding – can drastically cut the risk, particularly during spells of prolonged hot weather.