It was always going to be a shock to hear a man who has won two European Cups with Nottingham Forest publicly state that the club is no longer close to his heart.

But it should not be a surprise that the love affair between Martin O’Neill and Forest has soured.

In truth, it was a relationship that became untenable long before the straight-talking Northern Irishman revealed, live on radio, that his fondness for the club where he enjoyed his greatest successes as a player had been tarnished.

It is a sad state of affairs; an entirely unfitting, perhaps even final chapter to a story that should have had a happier ending.

From his point of view, you can completely understand why he admitted to feeling a sense of bitterness while a guest on Talksport. He was treated very poorly by a club that owed him more dignity and respect than he was given.

But like the rekindling and renewal of many relationships, it was always going to be a question of timing. And in O’Neill’s case, the timing could not have been more off.

His 19-match tenure ended with his standing in the eyes of many supporters diminished as well. The end of his six-month spell as manager damaged his relationship with a club that he should have had a lifelong bond with.

That does not mean that O’Neill is not deserving of sympathy or that it is not a shame that one of the Miracle Men who won back-to-back European Cups under Brian Clough in 1979 and 1980 (albeit that he was not selected for the first final), feels that his relationship with the club, under its current hierarchy, has been badly damaged.

It is more than half a century since O’Neill made his debut for Forest as a player and his career since has seen him forge emotional ties with the numerous other clubs he has managed: Wycombe Wanderers, Leicester City, Celtic and Aston Villa in particular and with the Republic of Ireland, who he managed for almost five years.

It felt like the natural order of things that he would have the same relationship with Forest, when he returned in January 2019. But it just never happened.

Ultimately, too much was pinned on the hope that his previous connection with a club that he last played for in 1981 could help to spark a fresh round of success with him in the dugout.

To the generations of fans who were too young to remember the glory days, the achievements of the past brought him precious little time when it came to what unfolded on the pitch.

Since he started a law degree as a young man in Belfast — before being offered his opportunity in football — O’Neill has always retained a keen interest in criminology and law. Over the years, he could occasionally be seen in the public gallery at court cases. He possesses a sharp, inquisitive mind. In press conferences, he could rankle at any poorly thought-out questions, but would always respond enthusiastically to topics he found interesting or stimulating.

The achievements of his career show that he has been, without question, a high-quality football manager. He won promotion twice with Wycombe and again with Leicester City, while also leading the Foxes to two League Cup successes. He was the most successful Celtic manager since Jock Stein. In five seasons in Glasgow, he won three Scottish titles, three Scottish Cups and a League Cup. The two titles he missed out on were by a margin of one point and by one goal.

His win rate of 75.5 per cent is the highest of any Celtic manager in the club’s history.

But he would have required little of his knowledge of forensic analysis to see that his impact at Forest was not what he would have wanted it to be.

Amid his latest comments, O’Neill referred to the 40 per cent win rate he had during his time as manager, which is entirely respectable. His tenure was a long way from being a failure. He did a reasonable job, without ever blowing anyone’s socks off.

He won eight of his 19 games in charge, as he guided Forest to a ninth-place finish in the Championship. But that does not tell the whole story.

O’Neill was appointed to win promotion and took over a team that was eighth. They lost four in a row at one stage and went down to mid-table, then they won the last three games to make it look a bit more respectable. But they didn’t reach the play-offs, or really threaten to, and the style of play was often hard on the eye.

His problems were encapsulated perfectly by the issue of Joao Carvalho, the then £13.2million ($16.5m) record signing from Benfica. He would regularly tell staff around the City Ground that ‘He’ll get you the sack, that boy’ — a phrase he repeated again on Talksport.

In a fashion, he probably did.

Carvalho regularly started on the Forest bench under O’Neill (Jon Hobley via Getty Images)

Carvalho was not worth £13.2m. He was a young man with bags of raw ability; he had an eye for a pass and the brand of creativity and flair that became synonymous with previous generations of Portuguese players.

He was also wildly inconsistent — something that has been underlined by his career path since. He remains a peripheral figure at Olympiacos, having spent last season on loan at Estoril Praia. But O’Neill’s refusal to use him only served to fuel the notion among fans that O’Neill was unimaginative and unexciting.

The fact that some fans were willing to label O’Neill a dinosaur during his tenure showed how little history mattered to the modern generation of fans.

The sadness of it all is only underlined by the fact that the club’s greatest-ever player, John Robertson, was the man who had persuaded O’Neill that it was time to return as manager to the club where he had spent a decade as a player. O’Neill had turned down the same opportunity on two or three previous occasions.

He had verbally accepted the role once, only to change his mind. But this time he was persuaded by his old pal, confidant and former assistant manager, that he should not miss the opportunity. The heart, perhaps, overruled the head for once.

If only it had been done on one of the previous occasions, the story might have turned out differently for a man who possesses old-fashioned dignity and decency.

But he was brought in to replace a popular figure, in Aitor Karanka, and, oddly, never quite achieved the same popularity himself. Many fans had campaigned for Karanka to stay and the club even asked influential figures among supporter groups not to sing his name once Karanka’s frayed relationship with the hierarchy led to his departure.

O’Neill was disappointed that he had not been given the duration of his 18-month contract to prove himself; he felt privately that if, at the end of that time, he had failed, he would have been accepting of whatever fate became of him. He regarded that as being the time he would get to prove himself, before assessing what came next, whether that be an extension or a parting of ways.

But the most telling time frame of all was not ultimately 18 months, but 18 minutes — which was the amount of time that passed between the announcement of O’Neill’s departure and the confirmation of the appointment of his replacement, Sabri Lamouchi.

It was quite brutal how O’Neill was sacked. He had no idea it was on the horizon until he was informed by then Forest CEO Ioannis Vrentzos. He had played ball with the club hierarchy over a number of challenging issues, including agreeing to leave goalkeeper Costel Pantilimon out of the side, as a favour.

One more appearance would have triggered a clause that involved Forest paying another instalment for Pantilimon, as part of the deal that had brought him to the club from Watford. Pantilimon ended up staying for another year, which would have cost Forest a significant sum in wages regardless.

O’Neill won eight of his 19 games in charge of Forest (Laurence Griffiths/Getty Images)

O’Neill was still sitting in his office, described as being shocked and distraught at the news, when he found out that it was now another manager’s office, which would be painful for any manager, never mind one with his deep connections.

In recent days, O’Neill took issue with the suggestion that player power was his undoing.

“There was this idea that it was player power at Nottingham Forest. Do me a favour. Player power at Forest? There was not a player strong enough or with the personality enough to usurp me,” said O’Neill in that Talksport interview. “It is just ridiculous to talk about it.

“The players did not get me out in the end. I believe there were a few non-descript players who sent their agents to talk to the CEO. More fool him for listening. Please do not give me this here about player power. It was a nice little narrative for local journalists, who latched onto it.

“If Henrik Larsson, Chris Sutton or Neil Lennon came to me and said, ‘I do not like the way you are dealing with things’, I would dismiss them. I might think about it. But when I have a crowd of non-descripts at Forest coming up and saying that, please, give me a break.

“Am I bitter about it? Absolutely I am. But player power… they are really good players, those lads. They have all signed for Real Madrid. Nonsense. They are all playing non-league football.”

But it was, in part at least, a factor that he had lost the support of the dressing room within weeks of taking the job.

The players were non-plussed when he arrived. Some had to Google him. Others were more interested in what his assistant, Roy Keane, would be like. The same had been true when O’Neill was appointed at Leicester two decades previously when he initially faced a backlash from players and fans alike. But crucially, while he was able to win around the dressing room at Leicester — to the point where he was eventually worshipped by the players — he never managed to do that at Forest.

Perhaps time would have changed that. We will never know.

In January, Forest signed a midfielder by the rather optimistic name of Pele on loan from Monaco. O’Neill ended that when the player, who was nursing an injury, missed a medical appointment. Another player was dropped after reporting so late he missed the team coach.

What brought the situation to a head was an old-fashioned training day on the hills of Wollaton Park.

In very Brian Clough-esque fashion, O’Neill had beasted his players, some of whom were either vomiting or close to it. The squad discussed sending a delegation of players to talk to O’Neill, to voice their concerns.

That never happened, but when Roy Keane, the assistant manager, subsequently announced his resignation without any obvious reason for his departure, it prompted questions among the hierarchy. Vrentzos was used to working with managers who had a large entourage. O’Neill was now only left with Seamus McDonagh, the goalkeeper coach.

Evangelos Marinakis had met O’Neill several times and was always impressed by his enthusiasm. But communication was not always O’Neill’s strong point. He could be difficult to pin down on the phone. Which was an issue at a club where many conversations were had over WhatsApp.

The club eventually did seek the opinion of some of the senior players, who voiced their concerns over his management, which proved to be the final straw.

One player had already voiced his concerns to a Forest fan he had met on holiday, which had also got back to Forest via social media. That player’s response, when he found out, was: “Good”.  This all sums up how strained things had become for some players.

O’Neill is not a manager of the social media generation. His playing success with Forest came at a time when it was still a rarity for games to be broadcast live on television.

He was perhaps the right man in the wrong era.

(Photo: Andrew Kearns – CameraSport via Getty Images)