Air India cabin crew have been warned they could be grounded if they are seen to be too fat during a compulsory medical check up.

Crew members aged over 40 have been told they must have their body mass index recorded by the end of the month, unions claimed.

Anyone out of shape will be barred from flying, the Sunday Times reported.

Staff have retaliated by demanding free gym membership, something that has not been provided for a decade.

A company spokesman said that BMI checks had long been a requirement and staff had always had to maintain a certain weight to fly.