A mother had to choose which of her two children to save when her car fell into a dyke and she escaped from the sinking vehicle through a window.
Rachel Edwards, who was six months pregnant at the time, managed to pull her two-year-old daughter, Isabella, from the car but then had to decide whether to get her daughter safely out of the water or go back to rescue her son.
When she made it to the bank, an ambulance crew who had arrived at the scene prevented her from going back in for her son.
Jack Brennan, who was 16, was later confirmed dead in hospital.
The family were on holiday near Boston, Lincolnshire, on August 19 when their car careered off the road after hitting a pothole.
Ms Edwards (39) said: "I took a deep breath and expected the car to stop sinking but as it went down I felt the car turn over. My window had been open, so I managed to get out and up to the surface."
She said she then managed to pull her daughter -- who was strapped into her car seat -- out of the car but in water that was 10ft (3m) deep, could not let her go and go back for her son.
"I tried to go back for Jack but I knew if I let go of Isabella then I wouldn't be able to get her back. I was just screaming and screaming," she said.
Two of Jack's friends, who had also been in the back of the car, managed to escape and run for help.
Jack had closed the window on his side of the car just before the accident to avoid waking his little sister, his mother said.
Ms Edwards was treated in hospital for minor injuries and shock, together with her daughter. Isabella was transferred to a hospital in Nottingham for further treatment, although she is now back at home.
Speaking after her son's funeral, Ms Edwards said she was filled with regret at not being able to save them both.
"I have spent every waking moment thinking about how I could have saved both my children," she said. Five days after the accident, Ms Edwards, who is expecting her next child in November, went to collect Jack's GCSE exam results.
Speaking about her son, she said: "He was respectful and always told the truth and he could be trusted immensely. Jack was a character who could not fade into the background."
At his funeral in Essex last week, more than 300 people lined the streets to pay their respects.
His mother said she was amazed that he had "touched so many people".
"I can imagine he was looking down and thinking, 'what a spectacle this is'."
Carl Brennan, Jack's father, who is separated from Ms Edwards, said he was devastated by his loss.
"You don't think you will ever have to bury your child."