The Chancellor was joined 15m below ground under the river Thames at North Woolwich by Crossrail Chairman Terry Morgan and Crossrail apprentices who have worked on the tunnels.

"As part of our long term economic plan we are investing in infrastructure around the country to create a more balanced, resilient economy," Osbourne said. "Crossrail is not only providing extra speed and capacity for London’s passengers, but also supporting new housing, jobs and businesses."

Boris Johnson, mayor of London, said: "London is the engine room of the UK and projects such as Crossrail are helping to drive our country’s economy in the right direction. Completion of The Thames Tunnel is yet another important chapter in the Crossrail story – a tale that perfectly highlights how investing in major transport schemes can trigger development and unlock the potential for thousands of new jobs and homes."

Since 2008 there have been planning applications within a kilometre of Woolwich Crossrail station for 4,286 new homes, over 70,000sqft (21,336sqm) of new office space and 114,000sqft (34,747sqm) of new retail space. It is estimated that the infrastructure project will generate at least 75,000 business opportunities and support the equivalent of 55,000 full time jobs around the UK, Crossrail stated.