Question to the Department for Transport:

To ask Her Majesty's Government what assessment they have made of the stability of Parkway Tunnel and of the approach tracks to the Network Rail Euston station during the construction of the HS2 caverns and tunnels directly underneath; and what steps they have taken to guarantee that there will be no disruption to the rail services into and out of the Network Rail Euston station during the construction of these HS2 works.

The Network Rail approach lines into Euston, including the Parkway Tunnels are located directly above the HS2 tunnels. Working in partnership with Network Rail, the Parkway Tunnels and Network Rail's railway tracks and systems have been the subject of Ground Movement Assessments by the HS2 Main Works Civils Contractor. The output of this assessment is currently being reviewed.

The design of the HS2 tunnels is being refined to minimise ground movement and settlement mitigation measures are being developed that will be compatible with the operation of the existing railway. The tunnelling is undertaken incrementally in small stages, which limits risk and means any settlement occurs in small stages allowing the existing railway infrastructure to be adjusted, as necessary.