Drivers in the UK urged not to leave water bottles in their cars this week

With hot weather conditions prevailing this week, drivers in the UK have been urged not to leave water bottles in their cars. It comes as the UK recorded the hottest day of the year so far, with the temperature levels soaring to 34.7C in London on Tuesday.

That seemingly harmless sip might actually expose you to toxic chemicals-and, in rare situations, could even ignite a fire, experts have warned. Motoring experts at Number 1 Plates warned that a parked car in warm weather can quickly reach temperatures over 50C -even if it feels mild outside. They said: "Most drivers wouldn't think twice about sipping from a bottle left on the seat. But when temperatures rise, that bottle becomes a chemical hazard - and surprisingly, a fire hazard too."

When exposed to heat, plastic bottles can release BPA (bisphenol A), a chemical associated with hormone disruption, fertility challenges, and even a higher cancer risk over time.

If the bottle's already been opened, things get worse: bacteria from your mouth can quickly multiply in the warm, damp environment, raising the chances of stomach bugs and digestive infections.

Dr. Stephanie Widmer, a board-certified emergency medicine physician and medical toxicologist, spoke to ABC News about the risk and said: "A bottle's manufacturing process, chemical composition, the outside temperature and how long the bottle has been exposed to heat means liquids could become contaminated with toxins."

According to the Met Office, England experienced its hottest June on record, while the UK as a whole recorded its second warm experienced its hottest June on record, while the UK as a whole recorded its second warmest June since measurements began in 1884.

Met Office Climate Scientist, Dr Amy Doherty, said: "While we've not conducted formal climate attribution studies into June 2025's two heatwaves, past studies have shown it is virtually certain that human influence has increased the occurrence and intensity of extreme heat events such as this.

"Numerous climate attribution studies have shown that human influence increased the chance that specific extreme heat events would occur, such as the summer of 2018 and July 2022. Our Met Office climate projections indicate that hot spells will become more frequent in our future climate, particularly over the southeast of the UK. Temperatures are projected to rise in all seasons, but the heat would be most intense in summer."