Dog walker finds a penny worth £150,000

A man out walking his dog has stumbled on the first-known pure gold English penny - hailed by experts as the most important find of a single coin for 100 years.

It was struck in London and bears the image of King Coenwulf, who ruled Mercia in central England 1,200 years ago. It was found on the River Ivel's banks in Bedfordshire. The exact location and the coin's importance have been kept secret from all but a few experts and archaeologists to avoid an invasion of "gold-diggers".

It was found in 2001 but now, following confirmation of its authenticity by the British Museum and other specialists - as well as settlement of ownership - the penny is set to fetch a new worldrecord-price at auction. Due up for sale next month and weighing 4.33g, it is estimated to be worth up to ?150,000. Proceeds from the sale will be split between the finder and the landowner. Both remain strictly anonymous.

Richard Bishop, coin specialist at London auctioneer Spink, said today: "The man who found it brought it to us and we fell off our chairs when we realised what it was. We couldn't shout about it because it is so important we would have started a gold rush. Other coins of this age have been imitations of Arabic dinars. This is the earliest purely English gold penny, as well as being the first to come to light for almost a century.

"Hoards of important coins from this period have been found but this is the most amazing accidental find of a single coin ever."