A schoolgirl was killed on her way to class when her friend drove into the back of a lorry. Emily Challen died almost instantly just four days before her 18 birthday.
A court heard that driver Aimee Culpin failed to see the HGV because she had been looking over her right shoulder at the traffic.
A-level pupil Emily – who was head of her house at Kesteven and Grantham Girls' School, which Margararet Thatcher attended – was in the front passenger seat.
The crash happened on a slip road off the A1 less than a mile from her family home in the village of Long Bennington, Lincolnshire.
Culpin, 19, broke down in tears yesterday as she admitted causing death by careless driving.
District Judge John Stobart sentenced her to 200 hours of unpaid work and a 12-month community order. She was also banned from driving for 18 months and must pay £150 costs.
Judge Stobart said: "This is a dreadful case. It is tragic, it is awful. Every person that sits in front of me today has been changed by it, and for the worse. It was a momentary lapse of judgment which could happen to any of us."
Lincoln magistrates' court heard that Culpin, who had passed her driving test just eight months earlier, had not been distracted by anything in her Vauxhall Corsa but had simply failed to spot the HGV.
Emily, who had a younger brother and sister, was studying business studies, art and English literature at the grammar school, where Lady Thatcher was head girl in 1943.
Her mother and father, Keith and Jennifer Challen, had planned to take her to the hit London musical Mamma Mia! for her 18th birthday.
Mrs Challen was at home getting the couple's 11-year-old son James ready for school when she received a phone call informing her of the accident. She drove straight to the scene.
In a victim impact statement, she said: "When I got there I saw in the distance a large lorry with Aimee's car embedded in the back of it.
"When I reached the car Emily was still in it. The corner of the lorry was sitting on top of where Emily had been. It was a horror scene.
"My daughter lying there with barely a pulse is something that will haunt me forever.
"I could not and still cannot understand how Aimee could have got her car into this position, causing the death of my daughter.
"Emily was my best friend and a soulmate. The family has been devastated. The death of Emily has left a massive hole in our lives."
Culpin was taken to hospital with an arm injury. Two other girls in the back of the car were not seriously injured and the 52-year-old lorry driver was unhurt.
After the crash, Emily's headmaster Graham Burks said: "Emily was one of our house captains, an iconic figure the girls admired and aspired to be like.
"She was very bright, very kind, a true leader among our students, a truly beautiful young person. We were all immensely proud of her. She was greatly loved throughout the school community."