Peterborough MP Fiona Onasanya has been sentenced to an immediate three months in jail after she was found guilty of lying over a speeding ticket charge.
The 35-year-old solicitor was accused of colluding with her brother Festus after her car was clocked going 41mph in a 30mph zone in the village of Thorney near Peterborough.
She was found guilty on December 19 and today was sentenced at the Old Bailey today.
Her brother, Festus Onasanya, was sentenced to 10 months in jail.
"It's a tragedy that you have found yourselves here and in this predicament but it's a tragedy that you have brought on yourselves."
Miss Onasanya, who is appealing against her conviction, gave no reaction as she was sentenced today.
Both Labour and Conservatives have since urged her to "do the decent thing" and step down.
A Labour Party spokesman said she had "let the voters of Peterborough down" and should have resigned when she was convicted in December.
"However, today's sentence gives Fiona one last opportunity to act honourably and resign from Parliament. She should do this without delay and not take another penny in salary from the public purse.
Parliamentary rules require the removal of an MP who is jailed for 12 months or more.
But with a lesser sentence, a recall petition can force a by-election if it is signed by more than 10% of the electorate in the Cambridgeshire seat.
Watch Emma Hutchinson's report below