It's believed Formula One star Jenson Button and his wife Jessica could have been gassed by robbers who targeted their French villa while they slept

The couple's rented home was burgled in St Tropez on Monday.

While they were asleep two men stole valuables - including an engagement ring - apparently worth a quarter of a million pounds.

Jenson Button's spokesperson says the use of gas by robbers is a growing problem in southern France.

Thieves pump anaesthetic through air conditioning units before launching raids on expensive properties.