Cracks and holes in the stones which form Stonehenge are to be repaired for the first time in more than 60 years.

Work is taking place after laser scans showed that the lintel stones, joints and concrete mortar that balance them across the vertical stones have eroded.

English Heritage’s conservation plan will prevent further erosion to the stones themselves and repair earlier works from the 1950s and 1960s.

Scaffolding will be used to access the tops of the stones in order to remove the old deteriorating mortar and repack joints with lime mortar to prevent the lintels and joints from suffering further erosion.

Heather Sebire, English Heritage’s senior curator for Stonehenge, said: “Stonehenge is unique among stone circles by virtue of its lintels and the special joints used to secure the lintels in place.

“Four-and-a-half-thousand years of being buffeted by wind and rain has created cracks and holes in the surface of the stone, and this vital work will protect the features which make Stonehenge so distinctive.

“Thanks to the sophisticated laser scan technology and our regular checks and monitoring, the stones will now be able to stand the test of time – and Salisbury Plain weather – for many more years.”

The conservation work will be carried out by Strachey Conservation, specialist conservators contracted by English Heritage and will take up to two weeks.

Visitors to the site will be able to see the conservation work in action.