Following three years of construction - which saw eight 1,000 tonne tunnelling machines bore 26 miles of rail tunnels under London - and decades of discussions, Crossrail’s labyrinth of tunnels is complete.

The next step is to finish the 10 new Crossrail stations and complete works above ground west of Paddington and east of Stratford.

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The station in Canary Wharf is not set to open until 2018, but the retail and leisure section, called Crossrail Place, opened its doors in May.

At the celebration event on Thursday, June 4, Mr Cameron said: “Crossrail is an incredible feat of engineering that will help to improve the lives of working people in London and beyond.

"The project is a vital part of our long term plan to build a more resilient economy by helping businesses to grow, compete and create jobs right along the supply chain.”

Mr Johnson said: “This is a landmark moment for London that puts us a gigantic step closer to the launch of an absolutely vital new railway, which will hugely improve our ability to speedily move people across our city.

“Crossrail has already created tens of thousands of jobs and helped boost the skills of many thousands of people not just in the capital, but all around our great nation.

"It is a wonderful example of our nation’s talent for engineering, a talent that must not be allowed to founder and that I hope will eventually be put to use on the construction of Crossrail 2.”

Crossrail facts:

  • When the network is completed, Farringdon will become one of the UK’s busiest rail hubs
  • More than 10,000 people are currently working on Crossrail, including over 450 apprentices.
  • Crossrail will add 10% capacity to London’s rail network and will serve 40 stations, connecting Reading and Heathrow in the west with Shenfield and Abbey Wood in the east.