JAILEDThe Peterborough MP was thrown out of the Labour Party after being convicted of perverting the course of justice.
She has been jailed for three months after a re-trial at the Old Bailey.
The court heard evidence Onasanya was texting as well as speeding, during the summer recess.
Onasanya is the first sitting MP to be jailed since Terry Fields was sentenced to 60 days for failing to pay his £373 poll tax bill in 1991.
Her brother Festus was jailed for 10 months for his involvement, after pleading guilty to the same charge.
Onasanya was elected as Labour MP for Peterborough in June 2017,
six weeks before committing the offence, in Thorney, Cambridgeshire.
BUT SHE STILL WON'T RESIGN !!!"When she was found guilty she should have immediately done the decent thing and resigned," he said.
"Today's sentence gives Fiona one last opportunity to act honourably and resign from parliament.
"If Fiona does not resign, Labour will support local residents in their efforts to trigger a by-election through a recall petition."
The Conservatives also called for Onasanya to resign as an MP.
"She cannot possibly represent her constituents from prison and should do the decent thing and immediately step down," a spokesman said.
"If she doesn't, we will campaign to use a recall petition to ensure that the residents of Peterborough can have their say in a by-election for a new MP."