The immigration minister Liam Byrne has pleaded guilty to using a mobile phone while driving.
Mr Byrne said he was discussing a deportation issue at the time but accepted this was no excuse and he should have pulled over.
He expressed his remorse over the incident and apologised for wasting the court's time.
The Liberal Democrats and Conservatives have so far declined to make political capital from the incident and the Home Office and Downing Street insist it is a personal matter.
The 37-year-old MP for Birmingham Hodge Hill was stopped on the city's Tyburn Road on July 6th.
He today pleaded guilty by letter to Sutton Coldfield Magistrates Court to an offence under the Road Traffic Act 1988.
The court fined Mr Byrne £100, reduced from the standard £150 because of his prompt plea and expression of remorse. He has also been ordered to pay £30 costs.
His licence has been endorsed with three penalty points, adding to three previously incurred.
The Labour government made it a specific offence to drive while using a mobile phone after research showed reaction times could be slowed by as much as 50 per cent.