A reckless novice driver sped the wrong way on a motorway on the hard shoulder before crashing into the car of a mother and her young child on a slip road, a court heard.

A judge was shocked by CCTV footage showing Mitchell Locke driving along the M25 in his black BMW for some distance until he smashed into the other car near Bean, Dartford.

Other motorists had seen him using his mobile phone at various times.

“The court asks one question,” said Judge Philip Statman. “What led to this horrendous piece of dangerous driving?”

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Locke, he said, had smoked cannabis within the previous 24 hours and claimed he was paranoid, believing he was being chased.

The 20-year-old apprentice electrician, of Bourne Park Close, Kenley, Surrey, was sentenced to 14 months youth custody and banned from driving for three years after admitting dangerous driving.

He drove against the flow of traffic between junctions two and four of the busy M25 and onto the A2.

“When the hard shoulder ran out you veered into the carriageway itself and this necessitated other vehicles taking evasive action,” said the judge.

Video: Watch the moment reckless driver Mitchell Locke sped down the M25

“You also used areas of the white hatch markings when the hard shoulder ran out before you were able to rejoin another section of the hard shoulder.”

Prosecutor James Ross said Locke eventually drove onto the slip road leading to Bean Lane, near Bluewater, where the BMW struck Gemma McCarthy’s Suzuki Swift shortly after 2.30pm on September 4 last year.

The victim was alarmed to see Locke’s car coming towards her driving erratically. She later told how she felt “absolutely helpless”.

After the impact she looked behind her and saw her two-year-old son’s car seat was lying across the rear seat. He was distressed and crying. The car was written off.

Ms McCarthy, 27, said Locke got out of his car.

“He just sat there on a kerb stone with a blank expression on his face as though he was waiting for a bus,” she said.

An ambulance arrived and Ms McCarthy was taken to hospital and treated for whiplash and cracked ribs. Her son escaped injury.

Judge Statman said modern technology allowed him to assess just how dangerous the driving was.

“It is an absolute miracle that no-one was killed or seriously injured by you during the course of this passage of dangerous driving,” he said.

“The public should understand that Parliament limits the sentence I can impose upon you in the sense that the maximum is one of two years in a young offenders’ institute.”

Locke will have to take an extended driving test before he gets his licence back.