The dual mode TBM, dubbed Evelyn, broke through into a pre-prepared shaft at St John’s Wood in London following a year-long 7.26km drive from Willesden.

The tunnel is part of a 32km network of new electricity cable tunnels below London, which are anticipated to be completed by 2018.

As per the plans, Evelyn will now be lifted out of the St John’s Wood shaft and transported by road to Wandsworth to start a 3.5km tunnel drive towards Wimbledon, in the capital’s southwest suburbs.

After its scheduled completion in about six months, the TBM will again be transported by road back to Wandsworth, from where it will set out on its final, 9km drive to Kensal Green.

The remaining 13km of the route will be handled by a second TBM, Cleopatra, which is tunnelling from South Tottenham, north London, to St John’s Wood.

The TBM crew includes a mix of personnel from Costain and its tunnelling partners, VVB and Joseph Gallagher.