It has started it’s 5-mile journey towards Greenford from West Ruislip in West London
HS2 has launched the first of six machines that will dig the high-speed railway’s tunnels under London.
The tunnel-boring machine was activated near West Ruislip railway station in the west of the capital on Thursday.
It is one of two TBMs which will dig a five-mile twin-bore tunnel to Greenford over the next 22 months.
Once they reach their destination they will be dismantled and lifted from the ground.
Another pair of machines will dig a tunnel from Old Oak Common to Greenford, and two more will connect Old Oak Common with HS2’s London terminus, Euston.
Each TBM will be operated non-stop except for bank holidays by 15 people working in shifts.
TBMs are traditionally given female names.
The machine launched on Thursday was named Sushila after local teacher Sushila Hirani.
HS2 Ltd chief executive Mark Thurston, who joined Ms Hirani in starting the TBM, told the PA news agency he was “enjoying the moment”.
He said: “It’s a big day for us.
“These moments come up not very often in your career.
“We’ve set three of our (TMBs) going north but these are the first two heading towards London.
“It’s an important step as we build the railway north and south from here.”
Mr Thurston said the project has had “momentum for 18-24 months”.
He went on: “For the civil engineering part we’re almost hitting the peak.
“Just the civil engineering bit alone has got more than 20,000 people working on it, and somewhere around 27,000-plus on the project overall.
“It’s very much a national endeavour and has momentum on multiple fronts.”
Asked if he was concerned by political changes in the UK, Mr Thurston replied: “I would expect any government really, if you’re investing in growing our economy, (would) see transport as a way of connecting our major cities.”
He said HS2 will help decarbonise transport as “clearly train travel is much greener than flying or having cars and lorries on the road”.
He added: “When you look at some of the broader policy challenges that the country has got and this or any government have got, I think HS2 is a big part of some of the solutions to those.