The allegations were as vindictive and damaging as they were utterly false. Yet they all but destroyed primary school teacher Brendan O’Brien.

Brendan, 45, had for 16 years been an exemplary teacher: popular with pupils and respected by colleagues.

Yet in just a year his reputation was shattered, he lost his job and became clinically depressed, prey to anxiety and panic.

Brendan O'Brien (pictured with his wife, Jane) had 18 charges made against him concerning child abuse

A £25,000 legal bill exhausted his entire savings and ate into those of his parents. His reputation unjustly besmirched, he and his wife Jane — who has two grown-up daughters by a previous relationship — had to give up their dream of adopting a child.

And this awful ordeal was caused by five boy pupils from his West Yorkshire primary school who accused him of sexual abuse.

It’s the worst accusation that could be levied against a teacher. And in today’s climate, where historic cases of the abuse of children are as prolific as they are disturbing, the police, quite rightly, had to act.

Yet the most cursory of checks would have revealed that his accusers were troublemakers: disruptive, aggressive, defiant and precociously sexualised.

But once the boys — present and past pupils aged ten to 12 — had made the allegations that their teacher had inappropriately touched them and instigated sexual activity, the machinery of the law was set in motion. And despite the complete absence of evidence, it would destroy the name of a good man in the process.

In January, a year after Brendan was first arrested, a jury at Leeds Crown Court acquitted him, swiftly and unanimously, on all charges. He had pleaded not guilty to 17 counts of sexual assault on a male child under the age of 13 and one count of causing or inciting a male child under 13 to engage in sexual activity.

Brendan and Jane's (pictured) lives were destroyed when the allegations against Brian were made

So how could Brendan be left with a life in tatters while five malicious trouble-makers are carrying on with their lives, without so much as a telling off?

These are questions Brendan and Jane, 43, a reflexologist and sales assistant, are asking themselves.

Brendan says: ‘When I was charged, I was no longer Mr O’Brien, a respected village primary school teacher. Instead, I was a pariah. I was too scared to leave the house. I became introverted, and I lost 2 st. Yet the boys who accused me have been able to hide behind a curtain of anonymity while my name was publicised.

I can never forgive Brendan’s accusers. I truly believe the youngest of them was acting in revenge, and then the other boys joined a nasty, ill-conceived vendetta to try to destroy him. Jane, Brendan's wife

‘My accusers should be punished for making false and damaging claims against me. But they are all carrying on as though nothing has happened while I have to piece together my shattered life.’

Shattered is the correct word: Brendan’s teaching contract was terminated in July.

‘I don’t know if I can ever face standing in a classroom of pupils, wondering if one of them is about to make a complaint,’ he says.

Brendan’s nightmare began in January last year. He had driven to school and by 6.45am was sitting at his desk, planning his lessons. One matter was preying on his mind: how to deal with a particularly disruptive pupil. Brendan had already spoken about him to the school’s headteacher.

The day before, he had called the ten-year-old’s mother, inviting her to school to discuss her son’s behaviour. It was getting virtually impossible to teach with him interrupting, shouting wisecracks and refusing to do any work.

Then an hour later, he was summoned to his head’s office. Facing him were two police officers.

‘I was told I was being arrested on suspicion of sexual assault on a minor,’ he recalls. ‘And the child making the accusations was the same pupil causing problems.

Brendan (pictured) had, for 16 years, been an exemplary teacher: popular with pupils and respected by colleagues

‘I was completely, utterly dumbfounded. But my first thought was: “This will all be dismissed when the police investigate it and realise there is absolutely no foundation in it at all.” ’

But in the space of 12 months his life would be thrown into tumult as 18 charges were made against him concerning the children, the first boy and four others the ten-year-old knew.

On that January day, Brendan spent nine hours in police custody where every aspect of his teaching style was scrutinised.

He had, on his own admission, a tactile approach. He explains: ‘I would often praise children by giving them a pat on the back or a tap on the knee. I’d never questioned that it was inappropriate. But this boy claimed I had touched him in a sexual manner.’

DID YOU KNOW? Child sexual abuse costs the UK an estimated £3.2 billion a year because of social care, health problems and legal bills Advertisement

Jane, his wife of ten years, was by now dealing with her own shock. Two-and-a-half hours after her husband was arrested, two officers arrived at their four-bedroom terrace house in Barnsley.

Jane recalls: ‘My initial thought was that Brendan had been in an accident. I asked if he was dead.

‘But when they said he had been arrested for sexual assault, I was floored. The officers had come to search our home for possible evidence and to seize electronic equipment.

‘My legs would hardly hold me up as the police rooted through our bedroom. It was horribly intrusive. Although I knew Brendan had done nothing wrong, I felt as though we were criminals.

‘They looked through my work files and took away our iPad, mobiles, a Kindle and memory sticks. They spent months examining them, but didn’t find a single suspicious thing.’

When Brendan arrived home at 6.30pm, he was exhausted and bewildered. Jane says: ‘He could barely speak. But I never once doubted his innocence. The claim was ludicrous.’

Both he and Jane were confident a short investigation would swiftly exonerate him. They told only close friends and family of the accusations.

Jane (pictured) says: ‘I never once doubted his innocence. The claim was ludicrous.'

But the nightmare escalated. Last March, Brendan was arrested again. A further four ex-pupils who knew one another in some way claimed he had inappropriately touched them and instigated sexual activity.

‘I had no idea why they would make up such malicious and despicable lies,’ he recalls. In April, he was formally charged with the sexual assaults against five boys: a ten-year-old current pupil; three 11-year-olds and a 12-year-old.

But their stories were inconsistent. Some attested the assaults took place while he was teaching, others said it was while he was alone in his classroom talking one-to-one with them.

And evidence read out in court supported the fact that each of the accusers was a known troublemaker. The youngest had boasted he would ‘get Mr O’Brien fired’.

I don’t know if I can ever face standing in a classroom of pupils, wondering if one of them is about to make a complaint Brendan O’Brien

One of the 11-year-olds had grabbed another boy’s genitals, exposed himself and pinned down a female pupil until she cried. Even his own mother admitted in a meeting at his school, after Brendan’s arrest, she’d seen nothing in her son’s behaviour to indicate he had been abused.

Jane recalls the fallout of the allegations. ‘Brendan had always been so full of life and very jovial, but overnight his character changed.’

Her husband — a caring step-father to her two daughters — barely spoke and became consumed by fear. He suffered from anxiety and tremors, and his GP prescribed antidepressants.

‘I felt utterly useless,’ says Jane. ‘But I had to be the strong one.’

Brendan endured further distress when a local radio station misinterpreted the charges against him and broadcast that he’d had sex with young boys.

And the case brought one devastating side-effect. Brendan and Jane — whose daughters are 19 and 22 — had long dreamt of having a child of their own. Jane had, however, suffered from fertility problems, and they had enquired about adoption. ‘But with abuse charges hanging over Brendan, we would never be considered,’ says Jane.

The legal proceedings consumed their savings, and Brendan’s parents — in no doubt of their son’s innocence — chipped in.

Brendan (pictured) says he became consumed by fear and was prescribed antidepressants for his anxiety and tremors

As the case approached, a swell of support buoyed them up. Brendan recalls: ‘Parents of ex-pupils would stop me in the street and give me a hug, all of them telling me they didn’t believe a word of the claims.

‘But I still felt terrified. My solicitor had warned me if I was found guilty I faced up to seven years in prison and my name would be tarnished for ever.

Mercifully, the jury took just an hour to dismiss each of the charges against Brendan. Jane was with her daughters in court and when the verdict came, she was euphoric. ‘I squeezed my daughters’ hands,’ she recalls. ‘I just wanted to run to Brendan and hug him.’

Justice had prevailed, but at what cost? ‘I don’t know whether I will ever completely recover,’ says Brendan. ‘Everyone who knew us supported me, but there will always be strangers who believe there’s no smoke without fire.’

Jane adds: ‘I can never forgive Brendan’s accusers. I truly believe the youngest of them was acting in revenge, and then the other boys joined a nasty, ill-conceived vendetta to try to destroy him.

‘And if this is what teachers face — and we are told that false sexual accusations against them are not uncommon — the whole profession must feel under threat.