"When I'm with my wife, which is regularly, we have no regular routine," the QC said from the witness box.

"We were driving back from Kent, a journey we make very regularly and who drives depends on circumstances of whether one of us is tired, has work to do or is reading.

"We have a home in Kent where we go for weekends in my former constituency."

When asked again if he recalled who was driving Lord Howard said: "I very much wish that I did, unfortunately I don't."

Because the couple were holidaying in Grenada they did not receive the notification letter until over three weeks after the speeding offence.

"I tried as hard as I could to remember who was driving. It was almost a month before. I simply couldn't remember.

"Neither of us has any desire to escape the consequences of our actions. I couldn't truthfully complete the form."

He has three points on his licence for speeding in 2014 and Lady Howard has an old conviction for the same offence.

"I have no incentive to dissemble about this matter. I'd rather the driver was identified. We frequently change over during the course of the journey. It's a 65-mile journey."