For nearly a decade Britain has been planning the most ambitious infrastructure project in Europe – a 250mph high-speed railway linking London, Birmingham, Manchester and Leeds.
As costs spiral and it becomes clear the scheme will come in years late, a government review is now considering whether it should be scrapped altogether.
We started at the beginning, at the enormous site being cleared to make way for a new station at Euston in London.
Picking his way through the mud and rain, Euston Programme Director Rob Carr set out his vision: “There will be 11 platforms, each with trains carrying over a thousand people.”
They have already exhumed 50,000 bodies from this site and demolished hotels, council flats, and even an award-winning local pub.
Could the government really change its mind after all that?
To find out more we headed to Rotherham for the Convention of the North, an annual meeting of northern leaders.
Infrastructure was top of the agenda, but guest speaker Boris Johnson didn’t make a single mention of HS2.
He instead quipped that his 145-mile train journey from London to Doncaster was quicker than a 66-mile trip from Liverpool to Rotherham.
Suggestive perhaps that he would rather spend government money on improved northern links than high-speed trains to London.
Manchester Mayor Andy Burnham told us that wasn’t good enough.
“We need North-South and East-West links across the North of England if we are to be truly set up for the future,” he said.
He left us with a warning for Westminster: “Don’t forget your promises to the North.”
Just a few miles from Rotherham we met with Becky Quartermaine, a resident of the Shimmer Estate, which has been left unfinished since news that HS2 would tear straight through it.
Despite the fact that the line isn't scheduled to reach the area for over a decade, the whole estate is in limbo while a decision over HS2 is made.
Becky says she just wants them to “make their minds up – yes or no. We’ve got to move on with our lives”.
Supporters of the scheme say that modern Britain can’t do without HS2.
It will improve connectivity; re-balance the North-South divide and take the strain off our creaking Victorian railways.
At the National Railway Museum, engineer Gareth Dennis told us that the point of HS2 wasn’t really speed, but capacity.
Taking slower local trains and freight off the main line will allow for faster, more frequent long-distance services and take the pressure off our motorways.
We also left the museum with an intriguing anecdote from the 1830s.
Surveyors for the original Manchester-Liverpool railway were set upon by angry mobs, with one being run through with a pitchfork.
Building railways has never been a straightforward business in Britain.
Historical precedent aside, HS2 has been beset with problems for years.
The scheme was sold to Parliament at a price of £57 billion, but just last month the official figure went up to £78 billion.
Several high-profile figures, including Prime Minister Johnson, have publicly said they think the final price tag will be over £100bn.
To get to the bottom of this, we met with a former HS2 Director who says he was sacked after speaking out.
Tasked with pricing up the land and property purchases required to build the line, Doug Thornton says he found multi-billion pound black holes in the budget.
Whole blocks of flats in London priced at a couple of hundred pounds; secondary schools for under a thousand pounds.
“This is public money, not monopoly money from community chest," he said.
HS2 Ltd say the National Audit Office looked thoroughly at the allegations made by Mr Thornton and found nothing untoward.
Their review concluded that HS2’s revised 2016 cost estimate was reasonable.
The Department for Transport has made clear that all options for HS2 are on the table.
The line from Birmingham to Leeds could be lost, the trains could be slowed down, or the entire project could be axed.
We understand it will deliver its verdict in the coming days.
Until then, everyone along the line will be holding their breath.
Could this really be the death of the high-speed express?
HS2 - Death of the High Speed Express? Tonight airs at 7.30pm on ITV