A British grandmother was found dead on her flight back from Spain in front of shocked passengers.

Fellow travellers suspect that the “fragile old lady” was already dead before boarding – given how she was slumped lifelessly in her wheelchair with carers holding up her head, one woman has revealed.

Petra Boddington, a wellbeing expert and personal trainer, first noticed the grandmother at the Malaga airport when airport staff and carers surrounded her.

The 89-year-old was pushed along the plane aisle by a member of staff, which allowed many passengers to catch a glimpse. She was seated in a special assistance seat at the end of a row.

“People turned in their seats and went, ‘oh my god, she looks dead’,” Petra told The Sun. Everyone felt that the woman was not fit to fly after seeing how she was uncomfortably curled up and doubled over.

The people sitting in front of Petra saw people holding the woman’s head up, Petra said.

Just before takeoff, the cabin crew allegedly raised fears that the woman had died then sounded the alarm for a medical emergency. The plane turned around and emergency workers rushed on board and pronounced her dead.

Her time of death remains unclear. The incident delayed many passengers’ journeys by almost 12 hours.

Petra, among other passengers, was left frustrated that the woman was allowed to board the plane given her frail condition, saying that staff should have noticed the signs.

Tracy-Ann Kitching wrote on Facebook: “easyJet – you are unbelievable! Why did you let a dead person on our flight?!”

The co-pilot reportedly told passengers he would compile testimonies to write up a report.

EasyJet confirmed that they were presented with a “fit to fly” certificate, so they had no reason to ban her from the flight – and denies allegations that she was already dead when she boarded.

Staff said they were assured by the carers that she was “just tired” and “unwell”.