The leader of Buckinghamshire Council has commented on the ongoing works to repair a ‘giant’ sinkhole above HS2 tunnelling works.

The 20ft sinkhole near the Shardeloes Lake opened up on May 13, prompting a pollution probe and concern from residents.

Two months on since it appeared, the HS2 is negotiating with the landowners to repair the hole, which sits 30m above the Tunnel Boring Machines.

Now the leader of Buckinghamshire Council Martin Tett has commented the situation following a letter he received from HS2.

He said: “It is important that HS2 reassures local residents that this area is now safe and quickly makes good the damage done to the local environment.”

In the letter, Mr Tett was told the HS2 and its contractors were working with the landowner and tenants “secure the relevant temporary access licenses so that we can carry out our remediation plan.”

The letter said: “In accordance with these access agreements, Align will carry out a photographic pre-construction survey of the whole route before any remediation works begin and our environmental experts will check trees in the historic parkland to ensure that the access route from the temporary compound to the ground movement area avoids Root Protection Areas (RPA) and adequate separation from any trees with nesting bats or owls etc.

"All grazing livestock will be removed from the field by the farmer before works begin and Align will provide traffic marshalls for the duration of the works to manage vehicle movements and pedestrians on the Public Right of Way.”

As part of the two-stage remediation works, existing soil material from the base of the ground movement will be removed before a “structural backfill of the area” with approx. 150-200 cubic meters using chalk material from one of the vent shaft construction sites at nearby Amersham shaft or Little Missenden.

After the land has stabilised after one to three months, landscaping remediation works will be carried out and 15 inch layer of subsoil and topsoil will be reinstated and tied into the glassland before the area is reseeded.

Fencing around the site will be retained until the grass establishes, the letter said.

The letter said: “These works are to restore and reseed the area and we do not expect there to be any long-term effect on the landscape or visual impacts of the scheme.

“Align would prefer to carry out these works during the dry summer period, when the impact will be reduced, so we are working with the two landowners and other interested parties to progress these works as soon as practicable.”