A fourth giant boring machine has arrived at the site of HS2’s Northolt Tunnel.

HS2’s first giant tunnelling machine broke through this week at the end of her 10-mile (16km) journey under the Chilterns, excavating the longest tunnel on the HS2.

A tunnel boring machine named Lydia finished digging a 853m long tunnel into HS2 Old Oak station.

Two HS2 tunnel boring machines have completed the first mile of twin bored tunnel in London.

Contractors working for HS2 have transported a 160t tunnel boring machine cutter head to a new digging site in a complex overnight operation.

Two 2,000t tunnelling machines digging the HS2 tunnel under the Chilterns have completed the first stage of works.