Aviation experts have expressed concern over how a 'state-of-the-art' Boeing airliner came to crash shortly after take-off en route to Britain from India.

The Air India AI171 flight is reported to have crashed shortly after take off from Sardar Vallabhbhai Patel International Airport in Ahmedabad en route to London Gatwick, having taken off shortly after 1pm local time.

It was carrying 242 passengers and crew when it landed in the northwestern city's densely populated Meghani area. Among them were 53 British nationals.

Flight tracking service FlightRadar24 said the plane reached an altitude of just 625ft before it began to descend.

'We received the last signal from the aircraft at 08:08:51 UTC, just seconds after take off,' it said.