Four Britons were injured - one seriously - after a water pipe exploded at a Costa del Sol hotel, the Foreign Office said.
Carol Gardener, 53, was passing the three-star Hotel Globales Cortijo Blanco in Marbella, southern Spain, when she was injured by the blast, according to a member of staff.
Hundreds of British holidaymakers were staying at the hotel, where three others were also hurt in the incident yesterday at about 9am.
Ms Gardener was taken to the nearby Costa del Sol Hospital but was later transferred to the Carlos Haya Regional University Hospital in Malaga.
A Carlos Haya hospital spokeswoman said: "The woman was admitted to hospital in a very serious condition and was put on artificial ventilation.
"She is suffering from burns and is badly injured."
The pipe was on the outside of the hotel and the damage caused by the explosion was limited, the member of staff said.
Emergency services attended the scene and police are investigating the incident, he added.
Holidaymakers described hearing a loud bang.
Ian Cartwright, 34, from Bromley, south east London, told the Sun: "We were having breakfast when we heard a massive bang, like a bomb going off.
"Outside the hotel you could see a big hole ripped out of the wall and the pipe torn in half. There were bricks scattered across the road. You could still see blood on the floor after they had taken the injured people away."
Marbella is a popular destination for wealthy foreigners, with many British families on holiday there.
A Foreign and Commonwealth Office spokeswoman said last night: "We can confirm four British nationals were caught up in the explosion today at Hotel Globales. All have received hospital treatment. Consular assistance is being provided.
"Three are being treated for minor injuries. One is seriously hurt, and that is Carol Gardener aged 53."