A crying toddler died after being crushed twice by an electric car seat when his mother's boyfriend became angry about the noise he was making, a court has heard.

Three-year-old Alfie Lamb died three days later in hospital having suffered catastrophic brain damage as a result of the incident.

The Old Bailey heard Stephen Waterson, 25, deliberately shoved the passenger seat of his Audi A4 into Alfie until he went "ominously quiet".

Waterson and Alfie's mum, former Northfleet School for Girls pupil Adrian Hoare, 23, who has lived in Gravesend and Chatham, are both on trial accused of manslaughter.

The court heard the pair were returning from a shopping trip with Alfie and friends Marcus Lamb and Emilie Williams in February last year when Alfie, who was sat in the rear foot well between Hoare's legs, started to moan that he had too little room.

Mr Lamb said he heard Alfie cry out "mummy" and make choking noises, he also heard Hoare slap him and the couple both shout at him.

Alfie, weighing two-and-a-half stone, died of "crush asphyxia" after being hit by the seat which at peak would have exerted more than 12-and-a-half stone in pressure.

Prosecutor Duncan Atkinson QC told the jury CCTV on February 1 showed all four in a dark Audi car travelling to the address and that before Alfie got into it he was “fit and well”.

Mr Atkinson said: “It follows that it was during that car journey that something happened to Alfie that compressed his chest and or abdomen so that he went from an active toddler to a very seriously ill and brain damaged one.

“It was caused by the front passenger seat of the Audi vehicle, Waterson’s seat, being moved back further into the rear side footwell at a time when, as was known, Alfie was in that footwell.

“In effect he was squashed by the car seat and suffocated.

“This movement of the seat was a deliberate action by Waterson who was angered by the noise and fuss that Alfie was making during the journey.”

He added: "Waterson deliberately moved his seat back again, and kept it in that reversed position, squashing Alfie, as he again showed signs of breathing problems until he went ominously quiet.”

When paramedics arrived at the family home in Croydon they found Hoare, Miss Williams and Mr Lamb, who was carrying out CPR on Alfie but soon made himself scarce.

Waterson had dialled 999 but had fled before paramedics arrived. He quickly sold the Audi.

Hoare told them Alfie had been in a child seat in a taxi and had fallen asleep, when he got out he was unresponsive and the driver left, she claimed.

This would later turn out to be a lie.

The jury heard Hoare and Waterson both ignored pleas from Miss Williams to check on him during the car journey.

After the incident Waterson pulled Alfie out of the car and Hoare said to him ‘what have you done?’, according to Mr Lamb.

Miss Williams, who later changed her original story about the taxi and said she had lied "out of loyalty" to Hoare, told the court she had urged her fiends to check on Alfie after hearing choking noises. Her concerns had been dismissed.

The court also heard Waterson used a false name when he visited Alfie in intensive care.

Before the machines keeping Alfie alive were shut off, Hoare asked Waterson to come but he didn’t come back to hospital again.

Then, 11 days after Alfie's death, Waterson sent text messages to Hoare saying he would take the blame for everything.

Mr Atkinson said: “On February 15, Waterson sent a message to Hoare which read ‘I say this I love you Adrian more than anything and I want this be with me and u blame me for it all.

"I understand as I ain’t perfect but I do anything for you am here if u [sic] want me police are gonna come talk to me spoken to officers and I gonna take blame for all. u were great mum and although we had ups and downs a amazing girl to me please never forget this."

The court heard after the text Hoare gave a different account of what happened.

And in a prepared statement relating to Alfie, Waterson said “he loved children, and would not deliberately harm a child."

Waterson and Hoare have admitted conspiring to pervert the course of justice by making false witness statements to the police in the wake of the death.

Waterson is also charged with intimidating a witness by assault, of Mr Lamb less than two weeks after the death.

Hoare is also charged with assaulting Ms Williams in mid February.

The trial continues.