Anthony Murphy was “gobsmacked” on Tuesday night when he discovered a never-seen-before henge monument in the Boyne Valley, not far from Newgrange.

Murphy is a subeditor with the Irish Farmers Journal and his discovery in a tillage field in Meath is being described by archaeologists as a once-in-a-lifetime event.

Speaking to the Irish Farmers Journal, Murphy said that he and Ken Williams of Shadows and Stone weren't out with the drone by accident.

“There were headlines in the UK about the possibility of sites being discovered given the drought. What happens is the moisture left in the soil lodges into the archaeological features – which makes the crop greener as it has more moisture than the soil around it."

These headlines, and the advice of an archaeologist, prompted him to fly his drone over the landscape to see if anything might show up.

“The main discovery is a giant henge about 200m in diameter that is unrecorded and has never been seen before. The image is just stunning. There are three sites in total in the field and a number of possible additional archaeological features too.

“When I saw it first I was like ‘what’s that? What the hell is that?’ It’s something I had never seen before. It is huge.”

What happens next?

Murphy has spoken with archaeologists about the discovery and they have told him it’s a once-in-a-generation discovery. Stephen Davis of the UCD archaeology faculty said that it is the most exciting aerial image of Irish archaeology he has ever seen.

The field belongs to a farmer who has a mixed operation of beef, sheep and tillage.

Archaeologists are poring over the images and Murphy has reported the find to the National Monuments Service, who are equally excited with the "new" site.

“There is a huge array of stuff in this small area of Ireland around Newgrange. This is just incredible. I’m still pinching myself.

“It’s the most exciting day for me in terms of monuments. I've been writing about and photographing monuments for 20 years. I would have said all that there was to find had already been revealed by archaeologists. I’m gobsmacked.”