The first giant tunnelling machine, 'Florence', of the HS2 project has completed its 10-mile journey beneath the Chilterns, marking a significant milestone for the rail development.

The Tunnel Boring Machine (TBM), weighed 2,000 tonnes and is one of 10 machines excavating the 32 miles of tunnel for the new railway.

The HS2 is designed to link London Euston with Birmingham, reducing travel times between Britain's largest cities and making way for more additional local services on the West Coast Main Line.

Oxford Mail: Chiltern Tunnel in November 2022Chiltern Tunnel in November 2022 (Image: HS2)

Two identical TBMs - Florence and Cecilia - were used to create the twin-bore Chiltern tunnel, stretching from the South Portal located near the M25 to South Heath in Buckinghamshire.

Cecilia will complete her journey in the coming weeks.

Rail Minister Huw Merriman said: “This ground-breaking moment for HS2 demonstrates significant progress on the country’s largest infrastructure project, with ‘Florence’ paving the way for faster, greener journeys between London and Birmingham.

He applauded the "hard work and dedication" of the 450-strong team facilitating a rail line that "will transform rail travel for generations to come."

Oxford Mail: TBM crew on FlorenceTBM crew on Florence (Image: HS2)

Designed specifically for the geologic conditions beneath the Chilterns, each TBM excavates the tunnel, lines it with 56,000 pre-cast concrete segments and grouts them into place at a rate of 16m a day.

This feat of engineering is matched by a team of around 17 people per TBM, running in shifts to keep the operation moving 24/7.

On the surface, more than 100 people manage logistics and ensure the smooth operation of the tunnelling project.

Sir Jon Thompson, HS2 executive chairman, said: “Today is an incredible day of HS2 and I’d like to thank the hundreds of people who’ve worked so hard over many years to make it happen.

“We’ve still got a lot of work to do, but historic moments like today really underline the huge amount of progress that’s been made and the fantastic engineering skills we have on the project.”

Oxford Mail: HS2 Chilterns Tunnel North Portal view looking southHS2 Chilterns Tunnel North Portal view looking south (Image: HS2)

Align’s project director, Daniel Altier, added: “The mining of the tunnel is a fantastic achievement for not only the Align tunnelling team but also the earthworks team who have managed chalk excavated from the tunnels and placed on site."

Approximately three million cubic metres of chalk and other material has been repurposed in the creation of a grassland restoration project at the South Portal.

This includes the development of 127 hectares of new landscaping, wildlife habitats and bio-diverse chalk grassland.

The breakthrough comes a week after HS2 publicised research showcasing the potential for a £10 billion economic upswing for the West Midlands over the next decade, chiefly due to increased development around the two station sites.