The intricately patterned phenomenon was spotted last Thursday by a local long-distance truck-driver, although a tour bus driver from Lincolnshire said he saw the crop circles a day earlier [July 23] as he drove along the Ouse Bridge.

"The field was normal one day, the next day the crop circles had appeared," revealed the truck-driver who wished to remain anonymous.

The crop circles have puzzled Howden farmer Mr Robert Huddlestone, of Grove Farm, owner of the 50-acre field.

"They cover about 80 square yards and are very intricate and precise," he said.

"I've never had a crop circle in this field previously, but someone must have spent a lot of time and a lot of hard work creating something as complex as this."

The shock appearance of the crop circles has apparently sparked intense interest with several light aircraft were seen circling low over the wheat field last weekend.

But Mr Huddlestone insisted neither he nor his staff had heard or seen any strange activities in the area in recent times.

He was quick to point out how close his wheat field is to the bank of the River Ouse and local roads, handy enough for any determined earthbound pranksters with creative abilities and time on their hands.