Meanwhile travellers by plane are emerging as problem drinkers, with 10% drinking 15 units or more on their flight.

Reasons given are nerves, the easy availability of alcohol on flights and that some just see it as part of their holiday, The biggest problem for all is that the alcohol has twice the intoxicating effect at 30,000 feet up than on the ground, so a big increase in disruptive passengers, the main reason for aircraft diversion, say the Civil Aviation Authority (CAA)

According to a survey of nearly 1,500 British fliers by Columbus Direct insurance company 40% said they drank on flights, with one in six of those feeling ill as a result, one in twenty needing help from cabin crew and one in ten needing medical treatment after landing.

Drunk passengers guilty of causing a flight diversion can be billed for up to £80,000 by the airline and face a jail sentence of up to five years.