Boris Johnson could face prosecution after being filmed driving on a motorway in his open-topped Lamborghini with his two young sons wedged together in the front seat.

The Tory MP and shadow minister for higher education was videoed by a passenger in another car on his mobile telephone, as he drove along the M6 near Rugby, Warwickshire.

Mr Johnson can be seen smiling and taking his right hand off the wheel of his dark-coloured Lamborghini Gallardo Spyder to wave, as a man shouts from another vehicle: "I love you, Boris."

The video was passed to the Sun newspaper, which posted it online. The passenger who took the video said: "I couldn’t believe my eyes. If there had been a crash it would have been awful.

"But Boris didn’t seem to give a damn. When he noticed I was filming him on my phone he took his hand off the wheel to wave at me. I was stunned.

"If the police had seen him he would have been in big trouble for sure."

A spokeswoman for the Central Motorway Police Group told Times Online today that it would be investigating the alleged incident.

"This allegation will be passed on to the Criminal Justice Unit to see if there is a need for any prosecution," said the spokeswoman.

"They will look at the video and see if they can get hold of the original. They will then talk to Mr Johnson to see what his version of events is. They will then decide if they are going to take it forward.

"The CJU are part of the Crown Prosecution Service so they can make the decision if they should prosecute or not."

A spokesman for the RAC condemned the practice of putting two children together into a front car seat, sharing one seat belt, and suggested it may be illegal. "It is grossly irresponsible, and it suggests to me that the man has allowed his optimism to get in the way of good sense," said the spokesman.

When asked if Mr Johnson had been spoken to by David Cameron, the Tory leader, Conservative central office was reluctant to answer. A spokeswoman said: "I don’t think we are going to be talking about it. I think it is seen as a personal matter, I have been told not to say anything."

Mr Johnson, 42, the MP for Henley-on-Thames, Oxfordshire, told the Sun last night: "The boys had a seatbelt on and I didn’t think they were in any danger. If anyone says I was speeding I want to see the evidence."

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