Victoria’s top road cop Ken Lay says he has to rebuild his credibility with the public after he was nabbed speeding through a country town last October.

Deputy Commissioner Lay says he kept the $245 fine a secret - he only confided with Chief Commissioner Simon Overland - until now because he was the front man in a heavily promoted Christmas campaign to keep the state’s road toll down over the holidays.

Deputy Commissioner Lay, who lost three demerit points for doing 80km/h in a 70km/h zone when he passed through the town of Tooborac on the Northern Highway, said it was his first blunder in 35 years of driving.

"One of the real problems I had at this time was we were launching Operation Raid, our biggest drink-driving operation leading into Christmas, so I made a very clear decision that I didn’t want to undermine it,’’ he told Radio 3AW today.