The Archbishop of Canterbury was convicted of speeding just days after the coronation of the King.
Justin Welby was ordered to pay £510 in total for exceeding a 20mph limit in the Kennington borough of Lambeth on October 2 last year, a court spokeswoman said.
The archbishop also now has three points on his licence after being caught by a speed camera in his Volkswagen Golf on the A3036 Albert Embankment.
He was convicted and sentenced at a private hearing at Lavender Hill Magistrates’ Court on Wednesday – the same day he condemned the Government’s plans to tackle the small boats crisis as “morally unacceptable and politically impractical”.
The conviction, which was first reported by the Evening Standard, also came just days after the coronation of King Charles.
Mr Welby admitted the offence online, was fined £300 and ordered to pay a £120 victim surcharge and £90 in costs, the court spokeswoman said.
The prosecution was conducted through the Single Justice Procedure – allowing the court to deal with the matter through written evidence in a private hearing.
A Lambeth Palace spokeswoman said the Archbishop was aware of the speeding offence but had not been notified that it had gone to court.
The spokeswoman said: “He has tried to resolve this and pay the fine three times.
“He has all the paperwork to prove that he has tried to pay.
“Admin errors seem to be causing problems.”