Breakthrough! HS2 workers celebrate as machine digging controversial railway's longest-ever tunnel completes 10-mile journey beneath the Chiltern Hills

HS2 workers are celebrating as the machine digging the controversial railway’s longest tunnel has completed its 10-mile journey under the Chiltern Hills.

Florence, named after nurse Florence Nightingale, was greeted with fireworks and cheers from hundreds of HS2 workers who gathered to witness the moment near South Heath in Buckinghamshire on Tuesday, after it was launched in May 2021 near Rickmansworth, Hertfordshire.

The machine dug one of a pair of tunnels with a depth of up to 80 metres that will be used for HS2 trains travelling between London and Birmingham. A second identical machine will break through in the coming weeks.

The moment is a poignant one for the line which has been mired in controversy – particularly after Prime Minister Rishi Sunak axed the beleaguered project’s Birmingham-Manchester leg last year amid spiralling costs and repeated delays.

The Government is ploughing £36billion saved into dozens of other transport projects – called Network North – instead, including filling potholes and improving east-west rail connectivity.

But a report by the Commons’ Public Accounts Committee (PAC) earlier said that the London-Birmingham leg, known as Phase One, going ahead will likely ‘not be value for money because total costs will significantly outweigh benefits.’

Workers hold up their mobile phones and take pictures as digging machine Florence completes HS2’s longest tunnel, a 10-mile journey

Members of the engineering team behind HS2’s longest tunnel wait for the machine to break through on February 27, 2024 in Great Missenden

Workers hold an Irish flag at the cutting face of ‘Florence’ the machine after it broke through on the Chiltern Tunnel

Digging machine Florence completed HS2’s longest tunnel, a 10-mile journey under the Chiltern Hills, in North Portal, near South Heath, Buckinghamshire

The Chiltern Tunnel breakthrough site ahead of digging machine Florence completing HS2’s longest tunnel

Hundreds of HS2 workers gathered at the North Portal to witness the breakthrough of ‘Florence,’ the inaugural tunnel boring machine (TBM) of the HS2 project

Rail minister Huw Merriman said today: ‘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 while supporting hundreds of jobs and apprenticeships along the way.

‘Today’s breakthrough of HS2’s longest tunnel highlights the momentum behind the project and the achievement is testament to the hard work and dedication of the 450-strong team helping deliver the line that will transform rail travel for generations to come.’

HS2 Ltd described Florence as an ‘underground factory’ with a crew of around 17 people working in shifts to keep it running constantly.

It excavated the tunnel, lined it with 56,000 pre-cast concrete segments and grouted them into position, moving at an average speed of 16 metres per day.

Florence, which has a diameter of 10.25 metres, will be dismantled over the coming weeks.

A worker wearing safety glasses and a HS2 hard hat pictured on the momentous day today

Members of the engineering team behind HS2’s longest tunnel celebrate

Florence’ is one of 10 machines digging over 32 miles of tunnel between London Euston and Birmingham

Some large parts will be reused in other tunnel boring machines (TBMs) but many will be scrapped.

The three million cubic metres of chalk and other material removed during the tunnelling is being used for a grassland restoration project at the site where the machines were launched.

Preparations are also under way for the launch of two more machines to excavate tunnels between Old Oak Common and Euston in the capital.

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

‘Once complete, HS2 will dramatically improve journeys between our two largest cities and also free up space on the existing mainline for more local trains.

HS2 Ltd described Florence as an ‘underground factory’ with a crew of around 17 people working in shifts to keep it running constantly

Florence excavated the tunnel, lined it with 56,000 pre-cast concrete segments and grouted them into position, moving at an average speed of 16 metres per day

Preparations are also under way for the launch of two more machines to excavate tunnels between Old Oak Common and Euston in the capital

Workers at the Chiltern Tunnel breakthrough site ahead of digging machine Florence completing HS2’s longest tunnel

Currently the only leg of the HS2 project set to go ahead is the London to Birmingham line

‘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.’

HS2 Ltd project client David Emms, who is responsible for the section of the route that includes the tunnel, paid tribute to the workers for their ‘immense feats of engineering’.

‘HS2 remains the biggest infrastructure project in the UK,’ he continued. ‘From tunnels to train stations to structures and systems, the scale and ambition of what we are delivering is unmatched.

‘What we are achieving today has helped to set new standards for the construction industry in the UK and around the world.

Workers pose by the cutting face of ‘Florence’ – this worker smiles while holding two thumbs up

HS2 Ltd project client David Emms, who is responsible for the section of the route that includes the tunnel, paid tribute to the workers for their ‘immense feats of engineering’

Florence was operated by HS2’s main works contractor Align, which is a joint venture formed of infrastructure companies Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick

‘Not only that, rail travel for the future is being set by us as well.’

TBM engineer Karine Ben Kemoun, from France, was controlling Florence when it broke through.

After waving an Irish flag – as is tradition when tunnelling projects are completed – she told reporters: ‘It’s feels good. I’m very proud. It’s a great achievement for the team.’

Florence was operated by HS2’s main works contractor Align, which is a joint venture formed of infrastructure companies Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick.

Four similar TMBs are being used for tunnels on the approach to London, while another two will work on Birmingham’s Bromford tunnel.

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