In a decade’s time, passengers on the new high-speed trains hurtling out of London will get just a burst of daylight and a glimpse of the Colne Valley landscape before disappearing back underground through the Chiltern Hills.
Today, in that three-mile stretch between future tunnel openings to the north-west of the capital, the £98bn HS2 project’s scale, engineering might and cost are all evident: both at the vast work site scooped out beside the M25 in Buckinghamshire, and in nearby waters and woods where protesters are still encamped to stop machines coming through.
What was billed as the formal start of construction of HS2 began in September, after years of design, preparatory work and demolition. Funds were finally released for major works for phase one of HS2 between London and Birmingham after the government reviewed its decision one more time, with Boris Johnson giving the go-ahead in February.
On Chalfont Lane, just inside the motorway, lies HS2’s biggest single work site, part of a £1.6bn contract to create just 15 miles of the proposed 330-mile network. An expanse of bare earth the size of 80 football pitches holds temporary offices and factories to treat excavated chalk and cast enormous concrete segments. The focal point resembles half an excavated stadium with two circular portals at one end: the start of a future 10-mile tunnel through the Chilterns.
Two giant 170m-long tunnel boring machines (TBMs) are being assembled in this arena. Simply getting this state of the art German technology to the start line has proved an epic challenge. HS2 will not put a price on it, but each TBM will have cost many tens of millions of pounds. Transporting the machines from the Herrenknecht factory in southwest Germany by truck and ship meant slicing them into parts: the giant cutter heads, with a diameter of 10.3m, had to be bisected and welded again on site.
Reassembly started last month and could take until spring, a giant Meccano set requiring a 600-tonne crane to complete.
“It’s a moving factory,” says Didier Jacques, construction director, and a veteran of the Channel Tunnel project. Behind the cutter head will be a control cabin, where more than a dozen screens tell the operators exactly what is going on. “It is pressurised like a submarine so we can work safely underground.”
The two machines, named Florence and Cecilia by HS2 Ltd, are a significant upgrade even on the beasts brought in to dig out London’s Crossrail tunnels: not just bigger but also capable of continuous boring to speed up the years of work, drilling onwards even as the 7.5-tonne concrete tunnel segments are sucked up and swung into place by hydraulic arms behind the cutter head.
Further back is all the machinery that supports the process – as well as a canteen and toilets for the workers labouring within, and a refuge chamber promising 24 hours of survival should anything occur underground. Human safety will be improved by a pioneering robot, dubbed the Krokodyl because of its jaws, whose job will include removing the pieces of wood used to space out the hefty concrete segments.
Segments are baked here not just for the tunnel walls but for a two-mile viaduct spanning the Colne Valley, leading south-east into London. While tunnelling takes much of the disruption out of sight and mind for the Chilterns, the viaduct will traverse the lakes and waterways of local nature reserves.
And its construction will not just affect its eventual location, as the ongoing protests are highlighting. To reroute power lines in its path, pylons must be removed from Denham country park, a job that meant building another bridge and route through woodland. Work was briefly halted last month by more ingenious construction – this time on the part of protesters. A mesh nest in a 30ft tall bamboo tower erected in the River Colne was occupied by veteran activist Swampy, before police moved in to end the standoff and allow the works bridge to be built.
Now, more trees lie in the path of construction, including a number of oaks where treehouses have been installed by protesters. Sam Smithson, who left a job in fashion design to join Extinction Rebellion, has been part of the camp since May. Sooner or later, she says, the protesters will be evicted and trees felled: “It’s looking more inevitable each day but they haven’t moved in yet.”
A cheerful Swampy, speaking before his arrest, said he hoped the protests would slow HS2 until the government decided to can the works: “I still think there is a very good chance they will cancel it: it’s unpopular already and more hearts and minds are changing now they see the devastation.”
Despite the government’s go-ahead for HS2 last year, the network’s future appears to perennially remain in doubt. A report last month by the National Infrastructure Commission, previously a solid backer of HS2, suggested it would be better to prioritise regional rail links above building the north-eastern leg, which would link Birmingham to Sheffield and Leeds.
Lord Adonis, the former Labour transport secretary who launched HS2 as a scheme in 2009, points to facts on the ground. “It’s going to be largely built … there are 250 construction sites between London and Birmingham, there is £10bn spent, parliament has just enacted the leg to go on to Crewe… and it’s consulting on the fine detail of the route to Manchester. A line linking the three biggest cities in the country is a certainty.”
However, the eastern leg’s fate will only be announced in the context of broader rail plans for the Midlands and north of England. Adonis believes the only question is whether it goes ahead now or in decades to come. “In terms of what the country’s going to look like in 30 to 40 years’ time, it’s one of the most critical decisions for 2021.”
Failing to build high-speed links east of the Pennines would, Adonis says, “be like the Victorians building railways to Birmingham, to Manchester, and leaving Sheffield and Leeds with the canals. In social terms, if it believes in levelling up, the government really needs to build the eastern leg. Or the east will be two centuries behind, and it will lead to an exodus of jobs and people.”
With many around the PM remaining hostile, and the Treasury eager for cost savings, the political battle over the cost and economic benefits of the railway will continue.
As will the physical standoff in Colne Valley. “We’re continuing building more treehouses and better infrastructure, so that they are weatherproof and people can stay as long as possible, with sleeping bags and tarps and stoves to keep going up there,” says Smithson. “The area is historically known for flooding, and we are expecting flooding in January and February. It will be a tricky environment for everyone, whichever way you look at it.”