Leon Khangura, of Norwich Road in Acle, appeared at Norwich Magistrate’s Court on Monday where he was accused of speeding on Broadland Way near Postwick on September 11 while in his black convertible Ferrari California.
He was found guilty of driving at 90mph in a 40mph zone, fined £550 and his licence endorsed with six points.
He was also ordered to cover costs of £620 and a £55 victim surcharge.
Mr Khangura was stopped by police with his cousin in the passenger seat at the time.
Both he and his cousin told the court it was not possible they were travelling at the speed the laser gun recorded the vehicle at.
And Mr Khangura’s solicitor, Simon Nicholls, argued that a mistake could have been made as the only person who had seen the recorded speed was PC Chris Alexander, who may have misread it.
But PC Alexander had earlier told the court he was using the laser for speed checks when he noticed a dark coloured supercar approaching.
He said the roof was down and used the laser device to record the vehicle doing 90mph.
He radioed his colleague Sergeant Mark Barney ahead to stop the vehicle.
Sgt Barney, who was working in an intercept role in an unmarked police vehicle, caught up with Dr Khangura and pulled him over at 8.46pm.
Dr Khangura told the court he had been caught after coming off the A47 dual carriageway and had slowed down.
He said it was “not possible” he was doing 90mph in the 40 zone.
Although he could not prove he was driving at the speed limit, he and his cousin both said they would have known if the vehicle was travelling at 90mph.
However, in handing down judgment the lead magistrate said the court was satisfied that the recording PC Alexander had seen was correct and found that Mr Khangura was speeding.
He avoided harsher punishment after the court found the road was not busy at the time the offence took place.