A car salesman clocked speeds in excess of 100mph as he weaved between traffic on the M2 while over the drug limit and with a child in his Mercedes.

Joshua Morriss was told by a judge he behaved like "a bullish idiot" as he tailgated, veered onto the hard shoulder and undertook other motorists between Stockbury and Faversham.

In what was described as a "spectacularly dangerous" action, the 30-year-old also drove along the hard shoulder.

But unbeknown to the Deal resident, one of those vehicles he passed was an unmarked police car, which then recorded his average speed over a distance of half a mile at 97mph.

As a result, he has kept his freedom but lost his job, his licence and can no longer drive his father, who has difficulty walking, around in his vehicle.

Morriss, said to have been selling cars for almost 13 years, pleaded guilty to dangerous driving and driving while over the specified drug limit when he appeared at Canterbury Crown Court on Wednesday.

After being pulled over by police, he tested positive for cannabis, giving a reading of 2.6 microgrammes (mcg) per litre of blood for the class B drug's breakdown product, delta-9-Tetrahydrocannabinol. The legal limit is 2mcg.

In the Mercedes A200, which appeared to have worn tyres, was a female passenger and a child, said prosecutor James Harrison.

Describing the manner of Morriss's driving on December 20 last year, the lawyer told the court: "Officers in an unmarked vehicle were travelling on the M2 between Stockbury and Faversham when a black Mercedes overtook them.

"It appeared to be driving aggressively and over the course of several minutes, it tailgated other vehicles and undertook, driving onto the hard shoulder at speed.

"At points, he exceeded 100mph and police recorded an average speed over half a mile of 97mph."

The court heard that Morriss, of Freemen's Way, stopped as soon as he was indicated to do so and was "immediately apologetic".

Despite the positive drug test, he was not slurring his words and engaged with police, leading to the conclusion that he was not impaired.

Tom Worden, defending, told the court Morriss was not a recreational smoker of cannabis but used it to relieve pain from a previous motorcycle accident which left him with metal rods in his arms and legs.

Since his arrest, however, he has been taking the drug legally on prescription.

Mr Worden said that Morriss not only helped to drive around his dad, who is on crutches with two broken heels, but also his long-term partner's autistic daughter.

However, neither role can now be carried out due to his disqualification. The court also heard he no longer works as a car salesman and is yet to find another job.

"He is remorseful and the first thing he did was apologise to the officers, and continued to do so," added Mr Worden.

"He tells me today he has committed a very stupid period of driving which could have had far more serious consequences than it did."

Imposing a three-month jail term suspended for 12 months, with a year-long driving ban, Judge Simon Taylor KC said he was sorry the loss of his licence would impact on the defendant's father.

But he told Morriss: "The facts of this case are disturbing. You were overtaking and driving aggressively, such that you drew the attention of police.

"You were seen to be tailgating other vehicles, undertaking and, what I consider to be the worst aspect, you undertook on the hard shoulder, which is a spectacularly dangerous manoeuvre.

"Not only did you undertake on the hard shoulder but the speeds were far in excess of those permitted.

"This wasn't driving at 77 or 80 but in excess of 100, with an average speed of 97 over the course of half a mile, and all of that while you had passengers in the car, one of whom was a child. It was a very bad piece of driving.

"I'm quite sure you didn't set out that day to engage in criminal behaviour. But you crossed the line from someone being in a rush to someone bullying and being bullish on our roads and that could create havoc or death.

"To make it worse you were driving over the limit for cannabis.

"But in that video [arrest footage] you were very apologetic to police and, in my assessment, you almost immediately realised what an idiot you had been."

Morriss, whose two previous convictions in 2010 and 2016 are cannabis-related, was also told he must carry out 80 hours of unpaid work, be subject to a four-month tagged curfew between 8pm and 4am, take an extended test to regain his licence and pay £500 court costs within 12 months.