A HELICOPTER spotted on a ridge a mile north of Brynaman was conducting routine maintenance and essential repairs on eroded peat bogs and the historic Offa's Dyke.

The dyke is a huge earthwork running roughly the length of the current border between England and Wales.

Considered to be one of the greatest engineering achievements of British history, It was constructed around 785 AD by Offa, the King of Mercia, to defend his kingdom against roving Welsh chieftans.

The Guardian was contacted by members of the public who saw the grounded helicopter surrounded by a variety of vehicles on Monday morning, leaving witnesses wondering what was going on.

The aircraft, operated by BIH (Onshore) Ltd., was assisting in a ground operation exercise, which required lifting bags gravel from a base point to pathways by air.

Company Operations Manager, Andrew Pickervance, said: “We operated at Hay Bluff repairing the Offa’s Dyke footpath, and at Hatterrall Ridge.

“This required the lifting of bags of aggregate from a base point to the pathways by helicopter.

“The second task was north of Brynaman and required us to move bales of heather as part of a project to repair eroded peat bogs.

“I am informed that the heather seeds germinate to re-establish the bogs over time.”

The operation was conducted in partnership with Brecon Beacons National Park.