Pam Tweedale was allegedly denied access to her medication and was given no food or water (Picture: Jam Press)

A 77-year-old British woman was kept overnight in a mixed-gender cell in Spain after losing her passport on the flight over,her family say.

Pam Tweedale realised the document was missing when she touched down in Madrid for a family holiday with 13 relatives who all flew together from London Gatwick on August 16.

She suspects it fell from her handbag after she put it beneath the seat in front of her on the Iberia Airlines flight.

The retired shop assistant immediately informed Iberia’s assistance counter at Madrid-Barajas airport but the passport couldn’t be found.

After being directed to airport authoirites,she and her daughter Sharon say they were detained and held in custody in grim conditions for 22 hours before being deported to the UK.

Sharon told MailOnline: ‘We were put in a cell with about 12 people who didn’t speak English,including men,and they switched the lights off at 10:30pm.

‘It was like an old-fashioned prison with metal bunk beds. I didn’t know if I was in there with murderers.

Pam and her daughter were forced to shell out hundreds to get home (Picture: Jam Press)

‘It was freezing,and we just had a flimsy sheet.’

She also claims authorities denied Pam – who suffers from asthma and recently had gall bladder surgery – access to her medication and was not given any food until she got to London Heathrow at 1.25pm the next day.

The family were forced to shell out £500 each for the pair’s return flights,with Sharon paying an additional £500 for a new set of return flights so she could join the holiday late.

Airlines typically don’t allow passengers back onto a plane to retrieve lost items after a set time.

Iberia Airlines, Madrid-Barajas Airport and the Spanish authorities for comment.