A metal detectorist who unearthed one of the largest ever hoard of Iron Age coins in Britain and decided to keep 23 of them as a “memento” will have his metal detector destroyed.

Groundworker Shane Wood, 62, found the treasure while on a walk in Chelmsford, Essex, in September last year.

Ashley Petchey, prosecuting, told Chelmsford Magistrates’ Court that “avid birdwatcher” Wood saw a feather fall from a buzzard and noticed a gold item in the field where it landed.

Wood went home to fetch his metal detector and made the discovery, placing the coins into a bin liner.

Mr Petchey said that the horde of 933 Iron Age gold Staters was “likely to be if not the largest then the second largest such find in Britain”.

He said Wood handed most of them over to the landowner but kept 22 Staters and one quarter Stater, with an estimated value of between £9,850 and £12,350, for himself.

Mr Petchey said Wood did not notify the coroner of the find directly, but instead told a man who used the land who in turn notified the landowner who said he would contact the finds liaison officer.

Prosecutors say Wood did not have permission to be metal detecting on the land, though he said he believed he did. Police became involved and officers who searched Wood’s house found 23 Iron Age coins.

“He admitted he knew the coins were treasure and he shouldn’t have kept the coins,” said Mr Petchey.

Mr Petchey said Wood had been interviewed by a treasure hunting magazine and there was a photograph of one of the coins. He said this coin was not among those handed to the landowner but was later found.

He had no idea what they were worth but he just thought given the fact he'd handed over hundreds to the landowner he would keep some as a memento

He said that Wood’s girlfriend Kim Holman, 61, had found it and put it in a jewellery box. Simon Nicholls, mitigating for Wood, described the case as “very unusual and almost unique”.

He said Wood’s hobbies include “birdwatching, looking for fossils and in a very amateur way metal detecting”.

He said that “some days” after Wood handed over most of the coins to the landowner “it appears that Mr Wood’s girlfriend had put some of the coins that she was cleaning on top of the fridge or the freezer of the house”.

“Shane found them and the mistake that he made was that he thought he would keep them as a memento,” said Mr Nicholls.

“He had no idea what they were worth but he just thought given the fact he’d handed over hundreds to the landowner he would keep some as a memento.” He said Wood reported the treasure find to a man he believed to be the landowner but actually “merely has permission to keep horses on the land”.

The man then told the landowner, Wood handed over the coins, and the find was recorded. “What (Wood) didn’t appreciate is that as the finder of the items on the land the obligation is to notify the coroner himself within a prescribed time,” said Mr Nicholls.

“He didn’t know that he had to do that.”

He said Wood “thought he had done the right thing” by notifying the people he had but that he had not fulfilled his legal duty to notify the coroner himself within 14 days of the find.

Wood, of Hanningfield Road, Great Baddow, Chelmsford, admitted the theft of 22 Staters and one quarter Stater.

He also pleaded guilty to failing to notify the coroner of the find of the 933 gold Staters under the Treasure Act 1996.

Presiding magistrate Ian Fuller said: “Detectorists should go about their business in the correct way.” He said that theft of artefacts is “not just from the landowner or the Crown, but it’s depriving the public of interesting archaeological information”.

“It’s important archaeologists can get in quickly and understand the site fully so a sense of context is discovered,” he said.

Wood was sentenced to complete 200 hours of unpaid work as part of an 18-month community order.

His metal detector was forfeited to be destroyed, and he was ordered to pay £200 to the court. Kim Holman, of Chadwell Heath, Romford, East London, admitted failing to notify the coroner of the discovery of one Iron Age gold Stater.

Mr Fuller, fining her £160 and ordering her to pay a further £139 in costs and a victim surcharge, said her actions were “foolish” but added: “We don’t see yourself as being a detectorist so we don’t see you should necessarily have been aware of the law in the matter.”