Shocking video footage shows a "crazy" driver undertaking a lorry at 100mph on a motorway hard shoulder near Orpington in pouring rain.

Stunned chauffeur Justin Scrutton, 47, caught the dreadful driving on his dash cam near M25 Junction 4 as he shuttled holidaymakers from Heathrow Airport on Sunday at around 7.40am .

Rear camera footage showed the blue Ford Focus careering towards the lorry in the 'slow' lane before swerving into the hard shoulder.

The driver sped past the Mercedes-Benz lorry before and returned to lane one, speeding into the distance in a spray of rainwater.

As the rogue motorist sped towards other vehicles, front dash cam footage shows their left indicator flashing - suggesting the driver was aware of the risky move.

Justin, who was driving a Mercedes-Benz SUV, said: "I was shocked.

"It completely took me by surprise, it was crazy.

"I thought 'what the hell is this person doing?' "They were driving so recklessly, I was sure I'd see them on their roof further down the road."

Justin, who lives in Dartford owns taxi company Justin Time Travel, said it was lucky nobody was killed.

He added: "If there had been a family on the hard shoulder changing a tyre, the driver wouldn't have been able to stop in time.

"Everyone would have been killed."

Justin, who has worked as a chauffeur for more than 20 years, claimed the car was doing at least 100mph.

He added: "I've driven around 1.5 million miles in my life and I've seen some crazy stuff, but never anything like that.

"The lorry was doing 56mph maximum and I was overtaking it, doing 70mph, so they must have been going at least 100mph.

"I can't see a justification for why anyone would do that. It was just stupidity.

"The hard shoulder is a refuge for you to pull into to sort your car out.

"I want the police to see it because this is going to kill someone if it happens again."

Justin played back the cam footage repeatedly but could not identify the car's registration number.

He reported the incident to police who are considering an investigation.

Kent Police have been contacted for further information.