Newcastle United are now reaping the reward after revealing they took the biggest gamble in Championship history and say they would have spent years outside the Premier League had they failed to win immediate promotion.

In a rare interview - and with what serves as a warning to relegated clubs - managing director Lee Charnley invited Sportsmail into the St James’ Park boardroom to pore over the latest accounts and explain the extent to which they rolled the dice and the implications had they not gone up under Rafa Benitez, who was backed with £55million in transfers and a wage bill of £80.3m.

‘It would have been a catastrophe, a bloodbath,’ stated Charnley. ‘The manager would likely have gone. This was a one-season gamble from his view as well.

Newcastle are now reaping the reward after taking biggest gamble in Championship history

Managing director Lee Charnley invited Sportsmail to pore over the latest accounts

‘Some of the players would have wanted to go. Matt Ritchie, for example, bought into this on the basis of, “One year in the Championship then I am going to the Premier League”.

‘And then we would have had Financial Fair Play. You cannot operate a business continually that has a wage bill higher than its turnover, it’s not sustainable.

‘We’d have had no choice but to recruit Championship players. Three teams then come down with more money than you and you end up on this cycle of trying to catch them. You have to reset financially. It would have taken years to get out of the Championship.’

Charnley, though, says the exceptional management of Benitez and support of owner Mike Ashley meant a mass cull of players and staff was avoided.

The club remains in talks with the Spaniard over committing to next season and, given their financial stability on the back of finishing 10th this month, it is thought an agreement will be reached. Both parties are said to share an ambition to challenge in the top half of the Premier League and they are planning on the assumption Ashley will be owner, Amanda Staveley having been dismissed as a viable buyer.

Accounts for 2016/17 filed this week reveal that Newcastle’s wage bill in the Championship actually increased by £6m to a Football League record of £80.3m, some £20m more than the second highest at Aston Villa and enough to put them around 12th in the Premier League for that season.

Charnley explained the extent to which they rolled the dice and the implications had they not gone up under Rafa Benitez (R)

They spent £55m on 12 signings and, while sizeable fees were recouped for Moussa Sissoko (£30m) and Gini Wijnaldum (£25m), the payment of those deals over several years meant just £44m was received on total sales.

The club were struggling to meet running costs in December and Ashley made another interest-free loan of £15m, taking his lending to £144m. They finished the campaign with a pre-tax loss of £47m.

But Charnley traces the decision to ‘put all their chips on the table’ back to the final day of the relegation season when Newcastle beat Spurs 5-1 in front of Ashley, who made a bee-line for Benitez after full-time.

Charnley says the exceptional management of Benitez and support of owner Mike Ashley (pictured) meant a mass cull of players and staff was avoided

‘There should have been a negativity around the club given what had gone before,’ said Charnley. ‘It was surreal watching us beat a team who were going for second place and beat them like we did.

‘We had planned a conversation with the manager after the game. The thinking could have been, “We have to scale back because the revenues have gone down”, whereas Mike was, “We are going for it”.

‘We talked through the game, “If we could get the manager to stay, get off to a decent start, fans behind you, you build momentum and it can develop a life of its own”.

‘So Mike’s priority was to keep Rafa. He said, “I am going to leave you two to get on with it, I’m going to support you and, come next year, I do not want to be in this league”.’

Newcastle won immediate promotion back to the Premier League in the 2016-17 campaign

There was tension in January when Benitez wanted to re-sign Andros Townsend from Crystal Palace for £12m but the cash in the bank was not there to do the deal. Newcastle tried to come to a loan arrangement with an obligation to buy if promoted, but they were also mindful of being left with a £70,000-per-week player in the Championship.

‘It’s not like we’re sat on a big pot of cash keeping it for a rainy day,’ said Charnley. ‘Money comes in, money goes out and what’s left is available to spend, it’s that simple.’

Newcastle went on to win the title - prize money was just £50,000 - and promotion bonuses of £10m were paid. Charnley, though, did not accept his own.

‘In simple terms, I accept my share of the responsibility for us going down,’ he said. ‘Steve McClaren was my appointment. Given the owner’s approach in terms of supporting the manager, me and the club, it just didn’t fit.’

There is no trophy cabinet in the oak-furnished room in which we sat this week. It will be 50 years next season since the club last lifted silverware.

Benitez was backed with £55million in transfers and a wage bill of £80.3m during that season

But Charnley revealed: ‘The players are now hugely incentivised when it comes to the cup competitions. We’ve made our view clear on the cups in the past but now - and we’ve said this to Rafa - it’s, “Have a go, try and win a cup”.’

For Newcastle to achieve that - and to challenge the European places - they will need Benitez at the club.

Charnley could not speak any higher of the manager, but he has also warned that progress must be gradual.

‘This year was about staying in the Premier League and now it’s about growing and improving year on year, but doing that within our means,’ he said.

‘Thats not to say there is a lack of ambition, because there definitely is ambition, it will just take some time.’

Club remains in talks with Benitez over committing to next season after securing 10th this year

Of the manager, he added: ‘He, and the talented staff around him, are incredibly professional, meticulous and focussed. We have seen the benefit of that.

‘What Rafa has certainly done is improve the group of players on a whole. I look at Jamaal Lascelles from when he came in and he’s made huge strides.

‘We have got a group now who have an incredible spirit, work ethic and a real togetherness.

‘If you look to improve going forward, it’s a real fight to get the balance between improving the quality of the individuals and also retaining that team ethic. To find the two is not always easy - and potentially very expensive.’

Having taken a leap of faith in the Championship, it is now about small steps in the Premier League.