Peterborough MP Fiona Onasanya has denied she would have been speeding in her car while using her mobile phone.
Labour MP Ms Onasanya, (35), told jurors she did not know who was behind the wheel of her Nissan Micra on the evening of July 24 last year.
It is alleged she lied to authorities to dodge a prosecution for driving 41mph in a 30mph zone near Thorney at 10pm that night.
In cross-examination, David Jeremy QC quizzed Onasanya about the possible candidates.
Onasanya confirmed that her mother, Paulina Scott, brother Festus Onasanya and friends and family could have had access to her car.
Mr Jeremy suggested: “You might have been driving your car that night?”
The defendant said: “That’s correct.”
The prosecutor asserted: “You were using your phone while driving?”
Onasanya replied: “I do not use my phone while driving which is why I do not believe it was me.”
Mr Jeremy went on: “You have not asked anyone else whether they were driving your car that night because it would have been a totally redundant question.
“You knew and always have known who was driving that car that night.
“You have always known that it was you who was driving the car that night, who was speeding and using the phone, so it would have been entirely fatuous to ask Festus or your mother who was driving.”
The politician denied the suggestion.
The prosecution has alleged the Peterborough MP schemed with her brother Festus to claim a Russian man was driving the car when it was clocked speeding in the village of Thorney.
Jurors have heard Aleks Antipow was in Russia at home with his parents at the time.
Onasanya has told the Old Bailey she left a notice of intended prosecution (NIP) at her mother’s Cambridge house for whoever had been driving to fill in, assuming she was in Westminster that day.
But her former communications manager Christian DeFeo has told jurors she was visiting him at his home in Thorney on the evening on July 24.
Labour whip Onasanya has told jurors she cannot recall the meeting, which was said to have happened on the first week of the summer recess.
She also told how she fell out with Mr DeFeo’s wife Caroline when she postponed a centenary celebration in Peterborough they were organising.
She explained: “I had asked her to assist me in organising different people attending this event. The city centre had been shut down for this event. When I asked her who would be coming she said she could not tell me due to data protection.”
On whether she had visited the couple on the night in question, she said: “It’s only based on the information that I now have. I would not say to them I did not but I cannot recall.”
Onasanya, of Peterborough, has denied perverting the course of justice.
Festus Onasanya, 33, from Chesterton in Cambridge, has admitted three charges of perverting the course of justice, including one relating to the incident in The Causeway, near Thorney, at 10.03pm on July 24 last year.
Earlier, Judge Nicholas Hilliard QC discharged a juror on health grounds.