Gay Haines had stowed her mobile phone in her hand baggage before her flight to Barbados and forgot to set it to flight mode. The mistake cost her dear. On arrival, she discovered that she had racked up charges of £1,095, twice the price of the transatlantic fare. “I had not used it to make or receive calls and when I opened it after landing there was no mention of any charges,” she says.

Haines is one of dozens of air and sea passengers who have received shock bills after their phones connected automatically to a satellite roaming network. While EU rules cap roaming fees outside Europe at €50, the legislation does not apply to satellite networks on planes and boats, which charge premium rates for data, wanted or not, unless customers actively switch off data roaming.