‘If you are lining up sexual activity when there are patients on the couch, when you are meant to be focusing on their clinical needs but are focusing on something else, I simply drew the line at that.

‘It’s not a matter of morality. This wasn’t slipping away into a quiet part of the hospital or even off-site. This was, for a good part, in busy patient areas. You have got to lead by example.’

By rights, Sir Leonard’s last day at work should have been marked with glowing speeches. Bold, plain-spoken and, above all, passionate about patient care, Sir Leonard always enjoyed a reputation for getting things done.

He championed change and pioneering treatment that saw Newcastle’s hospitals garner international renown and played a pivotal role in organising the UK’s first successful infant heart transplant.

Yet Sir Leonard recalls how on January 10 this year – just months after he first clashed with the Newcastle upon Tyne Hospitals NHS Foundation Trust chairman Kingsley Smith over the sex ring – his exceptional career was brought to an ignominious close.

For three decades, he had been chief executive of Newcastle’s hospitals but he now found himself being pushed out of the door on ‘extended leave’.

He was ordered to surrender the keys to his office in the city’s Freeman Hospital. The hospital was his life work; he helped plan it, he was its first general manager – at just 30 – when it opened in September 1977, and its wards were as familiar to him as his own home. After filling two bin bags with personal effects, he was escorted out of the building. By any standards it was a humiliating end.

Still bewildered, he asks: ‘Why was this guy with 52 years’ service, and an unblemished record, suddenly crashed out the door?’

He was accused of gross misconduct and finally sacked in June this year. But the allegations against him – said to involve bullying, among other things – were, he says, trumped up. The real reason for his removal, he claims, was that, at 70, his face ‘no longer fitted’.

That, though, would hardly explain his undignified exit.

It seems his strident views, uncompromising manner and failure to toe the line had finally caught up with him. Not that he regrets a thing.

The sex ring, which he believes played a part in his downfall, existed at Newcastle’s Royal Victoria Infirmary for four years. In the hundreds of emails exchanged, ‘going for a cappuccino’ meant intercourse and there were obscure references to ‘spreading Marmite’.

Sir Leonard became aware of its existence in early 2016. He learned that one woman was known as ‘the Madam’ and that there were fears that attempts were being made to ensnare other staff members. He was in no doubt the two consultants had to be summarily dismissed – but the trust board stated his ‘wishes would not be met’.

While the junior staff and non-medical employees resigned, the two consultants held on.

Sir Leonard claims the lacklustre disciplinary proceedings against them were effectively a foregone conclusion: the board had already decided they would keep their jobs.

Believing the proceedings were ‘not professionally handled’, Sir Leonard said he ‘cut across the board’ to commission an independent legal report into the process, which, when published, was critical of its handling. His unilateral action did not go down well with the board, he says, and ‘the mood music absolutely changed’.

But he claims the vast majority of doctors, nurses and other staff in the trust supported him. In the event, the two consultants left voluntarily. ‘They have work in the North East. I have no work in the North East,’ says Sir Leonard. ‘My career is over. They [the trust board] have destroyed my good name.’

Following a board meeting in December, Sir Leonard listened to a scolding statement which said that the trust needed a new chief executive with different skills and abilities. It said that staff were scared for their jobs; there had been bullying allegations and widespread loss of trust among doctors.

‘I have discussed the matter with a lot of healthcare staff since and none of them would agree with that,’ says Sir Leonard. ‘If I was the rotten soul they described, I would have fallen foul of the unions. But they had no problem with me.’

The trust has accused him publicly of inappropriate behaviour but won’t go into details. Sir Leonard says he too cannot divulge too much because ‘it will compromise my legal position’.

At his spacious but modest bungalow in Newcastle, the city where he was born and bred, Sir Leonard stressed he was a ‘12 hours a day, seven days a week’ man who hadn’t taken a proper holiday in 17 years. In truth, not even his detractors would doubt his commitment. He joined the NHS as a management trainee aged 18 in 1965 and rapidly worked through the ranks.

Then and now, he viewed his role as a kind of shop-floor manager, in touch with all levels of his workforce, from consultants to cleaners.

By his own admission he could be abrasive, just as he had a reputation as ‘a risk-taker rather than a box-ticker’. ‘But I’m a chief executive running an organisation with a £1 billion turnover, nearly 14,000 employees – and I can’t raise my voice or flash my eyes?’

Railing against the NHS’s risk-averse culture, he says: ‘There is a diminishing confidence in the NHS – we are losing the dynamics of risk. There’s a great deal of professional self-preservation now.’

He says the NHS is now laden with the ‘burden of bureaucracy’. Thirty years ago, though, it was still possible to achieve results without having to fight through a bureaucratic jungle.

In 1987, Sir Leonard was the driving force behind the country’s first successful infant heart transplant.

Kaylee Davidson was five months old and dying from heart failure. Two previous deaths nationally had led to a moratorium on complex infant heart surgery, but her desperate parents pleaded with Newcastle doctors to operate.

Sir Leonard recalls: ‘She was very bonny: tiny, but absolutely beautiful. The medics were saying, “We’ve got to do it, we’ve got to do it.” ’

The operation got the go-ahead after Sir Leonard persuaded then local health authority chairman Arthur Taylor to meet with then junior Health Minister Kenneth Clarke in a London pub. Mr Clarke gave his permission in a note which read simply: ‘Arthur, tell them to get on with it, Ken.’

The operation was a success, and within weeks the Freeman Hospital was designated a national centre for paediatric heart transplant surgery.

It is a measure of his standing that following his departure in January he was inundated with letters of support, including one from Health Secretary Jeremy Hunt.

And Newcastle MP Nick Brown said: ‘Sir Leonard has been a strong voice for the interests of patients and has built the hospital trust into the internationally renowned institution it is. He has my strong support and backing.’

Since his dismissal, Sir Leonard has thrown himself into his work as chairman of Newcastle’s Freemen of the City. ‘I am still disappointed by what happened,’ he says. ‘But I have a strong sense of civic pride and life goes on.’

A hospital trust spokeswoman said: ‘The trust refutes any suggestion that the hearing, its outcome or Sir Leonard Fenwick’s alleged views about it, played any part in the subsequent dismissal of Sir Leonard Fenwick for gross misconduct.

‘Sir Leonard was dismissed for gross misconduct after allegations of inappropriate behaviour, inappropriate use of resources, and range of governance issues were proven.’