Ancient sites and monuments in North Pembrokeshire dating back thousands of years have been blighted with graffiti, broken glass and an abandoned car.

A Bronze Age standing stone in the Pembrokeshire Coast National Park, Bedd Morris and a megalithic stone at Bedd Arthur, both Scheduled Ancient Monuments, have been the focus of police investigation after they were deliberately damaged over the past few weeks.

Pembrokeshire Coast National Park Authority Culture and Heritage Manager Phil Bennett said: “The distinctive arrangement of prehistoric stones at Bedd Arthur stands within the Preseli Hills, which is also a Special Area of Conservation and it’s very unfortunate that they have been defaced.

“The stone at Bedd Arthur had names scratched into it, whilst the six foot plus Bedd Morris standing stone was hit by a vehicle and knocked over.”

Park Authority Ranger (North) Richard Vaughan also commented: “A car was driven up an old trackway below the Iron Age fort of Carn Ffoi on Carn Ingli mountain and abandoned. The sump broke and a 200m black slick of oil contaminated a Site of Special Scientific Interest.

“The black BMW was a left on a bridleway, and is popular access route for locals and visitors alike.

“I’ve also had to clean up a popular parking site on Dinas mountain covered in empty bottles and smashed glass on the surrounding rocky area. There are grazing animals in the immediate area, and potential for harm to walkers.”

Off-roading on protected areas on the Preseli Hills, Dinas and Newport Mountain is always an issue, ranging from small motorbikes and off-road vehicles. There has also been household and garden rubbish dumped, from single bags up to a lorry load.

The Rangers have also noticed an increase in the dumping of hazardous waste, including asbestos.

A Cadw spokesperson said: “Scheduled Ancient Monuments are legally protected, and damaging them is a criminal activity. These prehistoric sites have been here for thousands of years. Cadw will be working with the National Park Authority and site owners to make good the damage as much as possible, although damage to historic sites is in most cases, irreversible.”

The Bedd Morris stone has now been removed at the request of Cadw to a safe, secure location.