The moment that caused the biggest concern came when the alarm bells stopped ringing. Beset by increasing costs and lengthening delays, Tottenham’s £1billion stadium suffered a fresh setback when the fire warning system suffered two critical faults: the software needed to be completely rewritten on a programme already so advanced that the existing workforce had no idea how to install it.

This was September 2018, a month after the original target date for Spurs to return home. Group operations and finance director Matthew Collecott claimed it was the “worst day of the whole project”.

Chairman Daniel Levy received daily messages at around 5am as those tasked with the responsibility provided updates of how many sprinklers and smoke systems had been installed in pursuit of the safety certificate needed to open and yet then, as today, he remains more circumspect about the issue which contributed significantly to a prolonged stay across town at Wembley.

“It would have been disappointing if we hadn’t got in last season and we were disappointed not to get in the previous summer, but I think it was just a timing issue,” he told Standard Sport. “The biggest issue was could we get all the financing together?

“Football clubs have the impression they are these huge businesses. The reality is we create a lot of noise globally but turnover-wise, we are relatively small.

“To take on a capital project of this nature, that’s why so few stadiums ever get built, certainly ones of this scale. It was the enormity of the challenge and I think when we started we didn’t realise what we were taking on.”

That process, outlined in a new book Destination Tottenham released on Sunday, began in 2001 when Levy became chairman and affirmed a need to redevelop White Hart Lane. Two years later, the club began negotiating deals to acquire the land — a process he believes totalled around 80 different property transactions, including one incident in which a warehouse under Tottenham’s ownership was broken into and turned into a drugs factory.

“We discovered it had been bolted shut from the inside and when we finally got in we found three acres of cannabis growing in there,” explains Levy. “We obviously had to call the police. The next thing we knew we were victims of a revenge attack when the water pipes on the properties we owned down the High Road were cut, which flooded them all.”

A perceived lack of support from Haringey Council prompted Spurs to submit what they described as a ‘Plan B’ application for the Olympic Stadium, an offer subsequently withdrawn when the rioting in Tottenham during 2011 sharpened minds.

After the dispute with Archway Sheet Metal Works was settled in March 2015, the club’s plans could finally kick into gear with renowned architects Populous, but the Brexit ­referendum a year later complicated things further.

“We never got a fixed-price contract because it wasn’t possible,” said Levy. “Brexit hurt us as well because a lot of the stuff for the fit-out, a lot of that was imported, so the cost went up [at least] 15 per cent. The veil around the stadium is a £32m aluminium contract to a ­German company. Brexit happened and that added 20 per cent onto it.

“But this wasn’t just an import or south of England programme. Most of the metal and concrete was from yards in Sunderland and areas like that. All the steel relating to the pitch was from up north. At one point, we had over 4,000 people working on site 24/7. The logistics of running a project of this scale on a fairly tight site was a massive challenge.”

As it was, Spurs eventually moved back in for their last five Premier League home fixtures of last season and the climax of a Champions League run which took them all the way to the final.

"Brexit hurt us because a lot of stuff for the stadium fit-out was imported, so the cost went up at least 15 per cent."

It is the dawn of a new era but also in some senses the end of the beginning. Levy wrestled with the decision to replace Mauricio Pochettino with Jose Mourinho last month as the club now look to add the one missing piece from years of exponential progress on and off the field: silverware.

To do so, Spurs must avoid the same financial constraints which hamstrung north London rivals Arsenal as they repaid costs from their Emirates Stadium build more than a decade ago.

Tottenham have guarded against that by refinancing more than £600m of loans which were originally due to be paid back by April 2022, instead converting around £525m into bonds which will mature over a 30-year period.

Levy insists that nothing much has changed in terms of Tottenham’s position in the marketplace, especially with a fixed sum ringfenced for transfers each season as part of the refinancing agreements.

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“The problem is it is also about squad size, English versus non-English, because we have the homegrown rule in the Premier League,” he said. “There are lots of circumstances why sometimes you don’t do a transaction. It wasn’t a case that we didn’t have money. We have to get rid of this obsession in England of spending money. It just doesn’t happen overseas.

“There is an amount we have allocated to spend each year in terms of net investment in the team. If you compare us to certain other clubs, they will have more money to spend. It doesn’t frighten us.”

Other sources of revenue are yet to be fully tapped. A deal for the stadium’s naming rights remains incomplete.

“We are only going to do a naming rights deal if we get the right brand, in the right sector, on the right money,” said Levy. “If we can’t meet those three criteria, we won’t do it. At the moment, we haven’t found a company that meets all three criteria. We are not really close to anything on that at the moment.”

"We’ll only do a naming rights deal for the stadium if we get the right brand, in the right sector, on the right money."

And the possibility of an NFL franchise moving into the stadium remains ­possible, with sell-out crowds for matches in the capital and Shahid Khan’s aborted attempt to buy Wembley proof that that an appetite for regular games in London is undeniable.

“It is up to the 32 NFL owners to decide whether they want to relocate a team to the UK,” added Levy. “They have made no decision on whether that is going to happen now or in the future. All I know is we have a fully compliant NFL stadium within our own stadium.

“We would love them to play more games in London and the two played at our stadium were incredibly successful. We very much hope, if not a team, that we will have more games. Our door is very much open.”

It took a while to get that door open, but Levy is at least now content, alarm bells silent for more satisfying reasons.