A van driver has admitted killing two young children and seriously injuring their mother in a motorway crash earlier this month.

Martin Newman, 41, pleaded guilty to causing the deaths by dangerous driving of Jayden-Lee Lucas, three, and his four-year-old sister, Gracie-Ann Wheaton, at 1.45pm on Saturday February 5.

He further admitted seriously injuring their mother, Rhiannon Lucas, in the crash on the M4.

The family, from Tredegar, had been returning from a birthday party when the car they were travelling in collided with Newman’s Ford Transit on the motorway between junctions 28 and 29 near Newport.

Newman, of Croeserw, spoke only to confirm his identity and enter his guilty pleas during a brief hearing at Cardiff Crown Court on Monday.

No details of the offence were given and Judge Daniel Williams listed the case for sentence on April 8.

Several of the children’s relatives were in the public gallery, and one yelled “Bastard” as Newman was led from the dock.

The two children were rushed to the intensive care unit at University Hospital of Wales, also known as the Heath Hospital, in Cardiff, after the crash.

Ms Lucas and the children’s father, who has not been named, were also taken to hospital.

Gracie-Ann suffered a cardiac arrest due to the severity of her injuries and died the next day at around 5am.

Jayden-Lee died the following Friday at 4.30pm.

In a tribute to Jayden-Lee, his cousin, Jamie Lucas, 19, said: “He was wonderful, creative and a kind soul. Turned the grey skies blue.”

In a previous tribute to Gracie-Ann, he said: “She was so young. She had a bright future ahead of her. She was such a wonderful child.”

He added: “She was very smart, she was very creative. She had a really great imagination as well. She was just fantastic to be around.”

A GoFundMe page set up to raise money for the siblings’ funeral has raised more than £14,700.