Once the celebrations died down following his landslide election victory in December, Boris Johnson’s thoughts will have swiftly turned to the issue which, alongside Brexit, is likely to define his early years in Number 10.
Having strongly suggested in the past that he opposed HS2, we might assume that his decision to give it the go-ahead only came after a great deal of soul searching.
The government insists HS2 will serve as the “spine” of a transport revolution that will deliver prosperity across the country, ensuring that places such as the West Midlands will thrive into the future.
But a very vocal opposition to the project – many of whom sit on the Commons benches behind Mr Johnson – are sure to be keeping a very close eye on its progress.
The PM is well aware that HS2 has been dogged by controversy since the idea for high speed rail was first hatched by the Labour peer Lord Adonis, who ironically is widely despised in Tory circles.
Its final cost is likely to be at least treble the initial budget, and the at times gross mismanagement of the project by HS2 Ltd was more than enough to see it binned in the eyes of many opponents.
Then there is the impact on rural communities to consider.
While HS2 has been broadly welcomed by the urban business community, spare a thought for residents in villages along the route, some of whom have already seen their homes destroyed long before a single inch of track has even been laid.
At the very least, they must be fully compensated for any disruption caused.
After years of costly blunders and misinformation, supporters of HS2 still have a mountain to climb if they are to persuade the public that it is worth all the time, effort and expense.
As recently as last autumn ministers were still clinging on to the preposterous budget of £56bn – a figure which it is claimed the Government knew at the time could not possibly be accurate.
The often repeated claims that the line will “level up” the country will be scrutinised every step of the way.
Mr Johnson’s new HS2 tsar will be tasked with making sure there is no repeat of the ineptitude that has seen HS2 waste a small fortune in taxpayers cash.
Ministers will hope that the boardroom overhaul at HS2 Ltd helps to get things back on track, particularly as far as the project’s finances are concerned.
Quite simply, now Mr Johnson has taken the plunge and backed HS2, he cannot afford to get it wrong.
He knows full well that he must be seen to be committing to investment in schemes to boost the economy outside London.
Scrapping it would certainly have been interpreted in some quarters as a snub to voters in parts of the country, including the West Midlands, who loaned him their votes last month.
It is easy to see why, from Mr Johnson’s perspective, HS2 looks like the perfect example of his commitment to making good on his election promises.
Only time will tell whether HS2 matches his bold vision.
If it does not, it could well go down as the biggest infrastructure disaster in British history.