Construction on HS2, the controversial high-speed railway, will get under way today, with a "shovels in the ground" moment.
The government-owned company HS2 Ltd has not revealed the site of the event where breaking ground will take place, but it is understood Prime Minister Boris Johnson will attend.
Mr Johnson said: "HS2 is at the heart of our plans to build back better - and with construction now formally under way, it's set to create around 22,000 new jobs.February: What impact will HS2 have?
"As the spine of our country's transport network, the project will be vital in boosting connectivity between our towns and cities."
HS2 will connect London with the West Midlands, Leeds and Manchester, and is the largest infrastructure project in Europe.
The aim is to run 18 trains an hour in each direction to and from London - at speeds of up to 224mph - compared to between two and six an hour on Europe's high-speed railways.
It involves the construction of more than 300 bridges and 70 viaducts for the London-West Midlands phase alone.
There will also be six new stations including Birmingham Curzon Street, and extensions for London Euston and Manchester Piccadilly.
However, the final bill for the service could reach £106bn, according to a report commissioned by the government.
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Mr Johnson gave HS2 the go ahead in February, despite already running billions over budget and years behind schedule.
The Commons gave a green light for construction to begin two months later.
Friday's event "marks a major milestone in this government's ambitions to "build back better" from COVID-19", according to Transport Secretary Grant Shapps.
He said: "Shovels in the ground to deliver this new railway means thousands of jobs building the future of our country's infrastructure.
"This fantastic moment is what leaders across the North and Midlands have called for - action to level up our country by boosting capacity on our railways, improving connections between our regions, and spreading prosperity."
The focus for the rest of the year will be on the city centre stations and the major construction sites, such as Old Oak Common in west London, which will intersect with Crossrail, which will eventually run between Reading, Heathrow and Essex.
HS2 Ltd chief executive Mark Thurston said: "This is a hugely exciting moment in the progress of HS2. After 10 years of development and preparatory work, today we can formally announce the start of full construction, unlocking thousands of jobs and supply chain opportunities across the project.
"We are already seeing the benefits that building HS2 is bringing to the UK economy in the short term, but it's important to emphasise how transformative the railway will be for our country when operational.
"With the start of construction, the reality of high speed journeys joining up Britain's biggest cities in the North and Midlands and using that connectivity to help level up the country has just moved a step closer."