A young boy was crushed to death by an electric car seat for being noisy, a court has heard.

Alfie Lamb was in the rear footwell of an Audi car when he was squashed “at the touch of a button” by Stephen Waterson, 25, who was in the front passenger seat, the Old Bailey in London was told.

In February last year, Waterson allegedly pushed his seat back twice in anger at the “noise and fuss” made by Alfie, who was three and a half years old.

The boy’s mother, Adrian Hoare, 23, who was in the seat behind her son, is charged with manslaughter alongside Waterson. Hoare, 23, did nothing to help her stricken son and lied to police about what happened, the court heard.

After emergency services were called, Alfie was rushed to hospital unresponsive and put on life support, which was switched off days later.

The Audi driver, Marcus Lamb, 22, told police how Alfie collapsed during the journey back from shops with his then-girlfriend Emilie Williams, 19, and the defendants.

He described how Hoare had been shouting at Alfie, who was screaming and crying. The witness alleged he heard Hoare slap her child before the front passenger seat moved back as Alfie called “Mummy”.

Lamb claimed he only realised there was a problem when they arrived at Adams Way in Croydon, south London. When Waterson pulled Alfie out of the car, Hoare said: “What have you done?” he claimed.

Duncan Atkinson QC, prosecuting, said a pathologist found that Alfie died from crush asphyxia.

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

“In effect, he was squashed by the car seat and suffocated. This movement of the seat was a deliberate action by Waterson who knew that Alfie was there and was angered by the noise and fuss that the three-and-a-half-year-old was making during the fateful car journey.

“The deliberate movement of the seat, by electrical operation by the touch of a button and involving the application of considerable force to Alfie, took place not once but twice.

“Waterson was prevailed on to move the seat forward again because it became immediately obvious that it was causing Alfie breathing difficulties. However, when Alfie made noise again, 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.”

Hoare had a duty of care to Alfie but did “nothing” to help him, Atkinson said.

She and Waterson went on to lie to police about what happened, the court heard.

Atkinson said it was immediately obvious to police and ambulance staff that Alfie had been dead for some time, even though Lamb was carrying out CPR.

Hoare allegedly told the paramedics: “We got into a taxi and put him into a child seat and he fell asleep. We tried to wake him and found him unresponsive.”

She said the taxi driver had “kicked us out” and left. Atkinson said it was “only the beginning of the lies that she, and others, were to tell”.

Police found CCTV footage which showed Hoare, Williams, Lamb and Waterson had all travelled together to Adams Way in a dark Audi car.

Atkinson said: “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.”

The court heard that Williams was later attacked by Hoare and Lamb attacked by Waterson.

Hoare denies manslaughter, child cruelty and common assault on Williams. Waterson has pleaded not guilty to manslaughter and intimidation of Lamb.

Hoare and Waterson, from Croydon, and Williams have pleaded guilty to conspiring to pervert the course of justice by making false statements to police.