A girls' night out ended in tragedy after the driver decided to pull up on the hard shoulder of the M1 in an argument over petrol money, a court heard.

Christalla Amphlett, who was 19 at the time, switched the engine off, flung open her door and sat with her legs hanging out as she continued to argue with passenger Maisie O’Flynn in the back, it was claimed

A jury at St Albans Crown Court on Tuesday heard how another vehicle ploughed into the back of the car, killing another teenage passenger on the back seat.

Chloe Palmer, who was sitting next to Maisie on the back seat, suffered a severe brain injury and died in hospital six days later.

Miss Amphlett - who is now 21, of Symphony Close, Edgware, pleaded not guilty to causing the death of Chloe on November 25, 2017 by dangerous driving.

She also denies a second charge of causing serious injury by dangerous driving to Maisie, who suffered a head injury and an injury to the right side of her chest wall.

Prosecutor Wayne Cleaver said that although the male driver of the Isuzu D-Max that crashed into the back of Miss Amphlett’s Renault Twingo that night had himself admitted offences in relation to causing the death of Chloe by his dangerous driving - the jury heard he may have fallen asleep - she also was responsible.

He said: “The fact that she parked her car on the hard shoulder created the conditions which allowed the collision to take place.

“The prosecution say she is as responsible as the other driver was.”

Mr Cleaver told the court Miss Amphlett was the designated driver in a group of young women who had gone out 'clubbing' in Watford on Friday, November 24, 2017.

At 3.30am on the Saturday morning she set off from Watford and headed north along the M1 towards St Albans with three young women in the vehicle. Chloe was on the back seat directly behind the driver. Next to her was Maisie and in the front passenger seat was another young woman.

The jury heard that as the vehicle travelled along the M1, the defendant and Maisie started "bickering” about petrol money.

Mr Cleaver said Miss Amphlett became “annoyed and irritated” and, as a result, decided to bring the car to a halt.

“She pulled over onto the hard shoulder on the M1 where it remained stationary for a few minutes,” he said.

The prosecutor said the front seat passenger made it clear they weren’t supposed to be there and told the driver to move on.

Judge Michael Simon was told Miss Amphlett drove back onto the carriageway but pulled up once more just south of junction 6, the Bricket Wood exit.

An electronic device fitted to the vehicle, which was like the black box of an aeroplane, later revealed it was stationary on the hard shoulder for 17 minutes.

On this occasion, said Mr Cleaver, the young woman in the front passenger seat got out of the car and sat on a barrier, but Chloe and Maisie remained on the back seat with the defendant behind the steering wheel.

He said soon after stopping the car, Miss Amphlett opened her driver’s door and turned in the seat with her legs outside.

The jury was told the vehicle’s lights were off, no hazard lights had been switched on and the stretch of the motorway where the women was not lit up because some overhead gantry lights were not switched on.

Because the Renault was not as far over as it should have been on the hard shoulder, it was close to the traffic and other drivers began to sound their horns to indicate it “presented a potential danger.”

Mr Cleaver said some motorists had to swerve because the open door of the Renault was so close to the roadside with Miss Amphlett’s legs outside.

The court was told the Isuzu D Max was travelling north along the M1 when it suddenly veered across the carriageway and into the back of the Renault.

Mr Cleaver said Miss Amphlett herself suffered a head injury and bone fractures as well as ligament damage.

He added: “The hard shoulder can only be used in circumstances where there is a genuine emergency. This was not an emergency. This was young women bickering in a car and getting agitated and showing off.

“There was no pressing need for the car to stop at that location,” he said, adding “without her parking in that stupid position this would never have happened.”

The jury was told that Miss Amphlett was interviewed by police in August last year.

In a prepared statement, she said “Looking back I don’t think my driving was careless or dangerous and was the cause of the collision.”

The first witness to give evidence was Keziah Knight, who was in the front passenger seat.

Miss Knight said it was on the afternoon of Friday November 24, 2017 that the friends arranged to go to a club in Watford that night.

She said that evening Christalla drove her and Chloe to the club and the plan was that at the end of the night the three of them would stay at Chloe’s home in Finchley.

At the club they met Maisie and spent the rest of the night there until closing time at around 3.30am.

Miss Knight, who was 19 at the time, said she drank 8 to 10 glasses of Vodka Redbull while in the club and said she was “drunk, but not drunk enough to be sloppy”.

She said when they left the club it was agreed they would first drive Maisie home to St Albans before heading back to north London.

As they headed along the M1 she said a row broke out between Maisie, who was on the back seat, and Christalla who was driving, over petrol money.

She said: “Maisie kept saying she didn’t have it on her and she would sort it out in the morning. Christalla kept on asking - it was like badgering.”

Miss Knight said the defendant appeared to be “angry and annoyed.”

She said “As it went on and on we thought this is serious, she really wants this money.”

Miss Knight said soon all four of them were involved in the argument.

The court heard it was then that the defendant pulled up on the hard shoulder for around two minutes before driving off.

She said the defendant and Maisie O’Flynn again started arguing and the car stopped again on the hard shoulder, this time for around five minutes.

Keziah then told how there was a third and final stop on the hard shoulder as the row continued, with all four of them shouting to get their point over.

Miss Amphlett, she said, was repeatedly asking them all to get out of her car.

She said after about five to 10 minutes she got out and went and sat on a silver barrier beside the hard shoulder.

“At one point Maisie got out to talk to me and then got back in,” she said.

From outside the Renault she said she could see the three inside still arguing and Maisie was crying.

It was then she said that she received a text message from Chloe who was inside on the back seat which said “She’s actually fuming.”

Keziah said she looked up from her mobile at that point and it was then that she saw the “truck” hit the Renault which was pushed along the hard shoulder.

She said in the impact Miss Amphlett was thrown out of her vehicle and was lying in the road.

Keziah said she checked on Christalla before going round the car to Maisie.

She said the emergency services arrived on the scene a short while later.

The case continues.