Andy Burnham, the mayor of Greater Manchester, has been fined and given six penalty points for speeding on the M62.
The Labour politician, tipped as a future party leadership candidate, was driving at 78mph on part of the motorway where the limit had been reduced to 40mph.
Mr Burnham said a closure of junction 10, which he normally used to exit the motorway, had forced him to suddenly change his usual route home to Golborne in Wigan.
He said he was “not aware of any variable speed limit in place” at the time of the incident on 7 July last year.
In a statement, Mr Burnham said he “only found out about it when the letter arrived in the post”.
But he accepted that he was “going too fast”.
“If I had been aware, I would not have been travelling at that speed,” he said.
“That said, I acknowledge that, at 78mph, I was going too fast and accept the court’s decision.”
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Manchester Evening News reported the case was heard at Manchester and Salford Magistrates’ Court on 14 March.
Mr Burnham was ordered to pay almost £2,000 in fines, charges, and costs.
He was also given six penalty points on his driving licence after accepting the single speeding offence.
The 53-year-old has been mayor of Greater Manchester since 2017.