Crossrail’s 26-mile tunnel marathon has entered the home straight with 750m to go before the big east-west breakthrough ends the digging operation.

The Mayor of London paid a visit to tunnel boring machine Victoria, 42m below ground at the new Liverpool Street Crossrail station to wish her well on the final stretch.

Boris Johnson said: “These hardworking beasts have slowly but steadily been working their way across London. The last time I saw them they were at Canary Wharf, and now nearly six million tonnes of earth has been excavated and their work is almost complete.

“With the government confirming this week the Crossrail 2 route is now safeguarded, and businesses and the public showing overwhelming support for the plan, we are moving even closer to delivering another much needed new rail line for the capital.”

Transport Secretary Patrick McLoughlin, said: “The scale and complexity of Crossrail’s tunnelling works is astounding and shows British engineering at its best. I congratulate all involved and look forward to the completion of the project which will play a vital role in driving forward our long term economic plan.”

Crossrail chairman Terry Morgan said: “Once the tunnelling is complete, we will turn our attention to fitting out the tunnels with the tracks, cabling and all the systems needed to deliver a fully operating railway.”

Tunnelling began in the summer of 2012. In total, eight tunnelling machines have been used to create the new tunnels beneath the capital. Once tunnelling is complete, the thousand tonne, 150m long machines will have excavated around six million tonnes of earth.