Bidding was fierce between three main contenders who pushed the price up from a reserve of £3,200 before the hammer finally fell at £92,000 (it rose to £113,815 after fees and taxes) at the auction at Whittlebury Hall, near Towcester, Northamptonshire.

The number plate has been held back until now but HRH1 was issued in 1946 to a driver in Hull.

A spokesperson for the DVLA, who was present at the auction described the bidding as "frenzied" between the two buyers in the hall and the eventual winner, a phone bidder.

The spokesman said: "The bidding was very exciting. Three people battled it out to get the plate - two in the hall and one on the telephone.

"It was especially interesting because one of the bidders who was actually in the hall didn't come in until quite late.

"He came in at £80,000 but dropped out after he decided he couldn't match the person on the phone."

The number plate 1 O will be auctioned on Friday with a reserve of £10,000.

Damian Lawson, DVLA Personalised Registrations' Marketing Manager, said the plate was a real collectors piece.

He said: "For the personalised registration connoisseur 1 O is arguably one of the rarest plates available.

"As such, we have set the highest reserve we've ever set on one of our auction plates, but one I am confident it will exceed it."

The DVLA's auction record of £254,000 is currently held by 51 NGH and 1 RH was snapped up by retired Surrey-based businessman Rob Harverson for £247,000 in September last year.

The plate was auctioned off to raise money for the DVLA - the organisation has raised £68 million since April last year by auctioning off previously unissued numbers. It earned £84 million in 2007/08.

The regal-sounding number plate was sold at the DVLA Personalised Registrations auction at Whittlebury Hall, Northampton.