Relatives and teachers have been paying tribute to those killed
The parents of two gap-year students killed in a bus crash in Ecuador have paid tribute to their daughters.
Emily Sadler, 19, was described as "fun-loving and popular," while Indira Swann's parents said their 18-year-old "filled the room with warmth".
Two other gap-year students - Lizzie Pincock, 19, of Somerset, and Rebecca Logie, 19, of Lancs, were also killed.
Travel guide Sarah Howard, 26, from Cheshire, also died in the crash on Saturday, which injured 15 others.
Miss Sadler's family said in a statement: "She was a beautiful bubbly girl with her whole life ahead of her. Her loss is indescribable."
The student, who lived in Northwood, Hertfordshire, with her parents, two sisters and two brothers, attended North London Collegiate School in Edgware.
Greg and Louise Swann read out an e-mail from Indira
She was on a gap year before going to Manchester University to study history.
In a statement, her school said she had done exceptionally well in her exams and had tremendous potential.
Meanwhile, the parents of Miss Swann told of their pride in their daughter.
Her father, Greg, told the BBC: "There are just so many wonderful stories we could tell about Indira. That she was so generous, caring. She was a joy to be around.
"We were so proud of her, she was her own person, she was independent and she did the travel with our full blessing with our knowledge of the risks."
"We have no regrets about her going other than the final outcome," Mr Swann added.
The boyfriend of Miss Pincock, another of the students killed, said she raised the spirits of everyone around her.
James McLauchlan, 22, told the BBC: "She always had the effect - especially on me and some of her other friends - that she brought other people up around her.
"If you were down or wondering about yourself - you had self-doubts - she would be the one that gave you the pat on the back and give you the get up and go that you really needed."
Miss Pincock was a prefect at Taunton School in Somerset and her head teacher, Dr John Newton, said she was a gifted pupil with an exceptional future ahead of her.
Prime Minister Gordon Brown and Foreign Secretary David Miliband have both offered their sympathy to the families of those killed.
"It's every parent's worst nightmare to be going through what they are going through now," Mr Miliband said.
The group was almost three weeks into a 15-week trip - an Inca and Amazon adventure involving language tuition and working on a series of volunteer projects.
The accident happened at 1930 local time on Saturday (0130 BST Sunday) in Sancan, on the road between Manta and Jipijapa.
The group had been heading from Quito to the coast when their tour bus collided with a lorry.
One survivor told the BBC: "I was asleep, as were most of the people on the bus. I remember a big bang and the whole bus shook, and everything just stopped."
Of the other people injured, 12 Britons, a French national and two Ecuadorians suffered whiplash, minor facial and leg injuries.
Ecuadorian authorities have begun an investigation into the cause of the crash. British diplomats are said to be assisting them.
Ecuadorian police said the driver of a lorry carrying a load of sand crashed into the bus.
It is thought the lorry driver then fled the scene and police said they had recovered both the lorry and its license plate. It was unclear whether the recovery would lead to a prosecution.
The holiday was organised by the Warwick-based tour company VentureCo, which specialises in gap-year trips.
Its director, Mark Davison, said: "I think it was just an unfortunate combination of circumstances. It's a tragic accident."
Anyone concerned for the safety of a relative in Ecuador can call the Foreign Office on 020 7008 1500.