Shortly after 10pm on 24 July last year, Ms Onasanya’s Nissan Micra was allegedly caught by a speed camera doing 41mph in a 30mph zone in the village of Thorney, in Cambridgeshire.
Ms Onasanya, 35, was sent a notice by the police informing her they could prosecute her for speeding.
The letter was sent back naming Russian citizen Aleks Antipow as the driver, jurors heard.
But the court was told Mr Antipow was at home with his parents in Russia at the time.
Prosecutor David Jeremy QC said Ms Onasanya was connected with Mr Antipow through a property she and her brother, Festus Onasanya, had rented in Chesterton, Cambridge.
Mr Antipow had lived at that address between August and September 2016, jurors were told.
The contact details given for Mr Antipow were not his address and telephone number, but were connected to the defendant’s brother, the court heard.
Mr Jeremy said: “The purpose in providing the name of a real person as the driver, but providing a false address and telephone number that were connected to Festus Onasanya, was that Mr Antipow, while a real person, would remain untraceable to the police, and so the true driver of Miss Onasanya’s car on the 24 July 2017 would escape prosecution.”
Ms Onasanya’s sibling, a 33-year-old musician, had also used the same tactic when his car was caught speeding on 17 June and 23 August last year, jurors were told.
“It must, as some of us may know, be very irritating to receive that bit of paper telling us that we have triggered a speed camera and asking us to name the driver of the car,” the prosecution said.
“But while irritation is understandable, telling lies to frustrate an investigation into an offence is not.
“What Miss Onasanya did when her vehicle was trapped on the 24 July 2017, was not just to own up and tell the truth, which would have been so much better, but to adopt her brother’s method of evading prosecution.
“The two of them were acting jointly in telling lies in order to prevent the prosecution of the true driver.”
Last Monday, Onasanya, 33, of Chesterton, Cambridge, pleaded guilty at the Old Bailey to perverting the course of justice in relation to the two occasions when his car triggered speed cameras, and in relation to the 24 July incident.
Mr Jeremy told jurors: “The question for you to decide in this case will be whether Festus Onasanya was acting alone when he perverted the course of justice in relation to the trapping of Miss Onasanya’s car on the 24th, or whether the two of them were acting together.”
Ms Onasanya won her marginal seat with a majority of just 607 votes in 2017. As a Labour whip, she is responsible for party discipline.
Additional reporting by PA