A 30-year-old "well-loved" nurse has died after being taken ill while travelling to Dubai for a holiday.
Charlotte Carter, from Swansea, who worked for the NHS in north-west London, began to feel unwell while on a flight, friends said.
Her condition worsened on the taxi journey to the hotel and she was taken to hospital, where she later died.
The Foreign and Commonwealth Office said it was providing support.
Ms Carter did not have insurance so friends and colleagues are raising funds to bring her body home.
'Out of blue'
Paying tribute on Facebook, friend Kate George, who was due to meet Ms Carter in Dubai, said: "Charlotte was on the flight messaging me saying she can't wait to see me and planning our week.
"She was absolutely fine, even on top form and this happens completely out of the blue.
"A tragedy doesn't even describe what's happened to our beautiful, witty, charming girl."
A post-mortem examination is due to be held to determine the cause of death.
Ann Sheridan, from the Central and North West London NHS Foundation Trust, said Ms Carter was a "dear colleague".
"Charlotte did not have travel insurance which means that the medical and repatriation bills will be very high, estimated in the region of £40,000, increasing with each day that passes," she added.
A Foreign and Commonwealth Office spokesman confirmed it was "supporting the family of a British woman following her death in the UAE" and was in contact with the Emirati authorities.