There cannot have been many problems in Kathryn Benwell’s life that she did not believe herself capable of solving.

Grammar school-educated, fiercely intelligent and spectacularly successful, she had worked her way through the male-dominated world of banking to become a managing director at the American investment bank JP Morgan at a time when just 17 other women held the rank across Europe.

Hers was a world of high-stakes decision-making, transatlantic flights and the material trappings to match, from a beautiful village house in Kent to horses and a Range Rover on the drive. ‘I had the dream of a life,’ she says.

And yet, three years ago, this hugely capable woman would find herself lying in hospital with a broken back and ribs after being violently attacked by her husband – and still hesitating over whether to press charges.

‘I remember thinking, “I’m going to throw my husband in prison for this. Is this really what I want to do?” ’ she recalls now.

It is perhaps the most chilling illustration imaginable of the psychological grip an abusive man can exert over his victim.

For by then, Kathryn had already been subjected to years of violence, on one occasion beaten so savagely that her nose and several bones in her face had been broken.

During what would prove to be that final attack, he had forced a bottle of wine down her throat so violently that she believed she was going to drown.

‘Even then, I remember thinking at least it was white wine as it would be easier to clean out of the carpet so he wouldn’t be angry about the damage,’ she says.

Today, looking back, Kathryn – a poised, articulate and glamorous 59-year-old – can see with painful clarity the textbook progression of the domestic abuse which almost destroyed her life: from the charm and love-bombing to the isolation and financial manipulation and, eventually, the terrifying physical violence.

At the time, however, she saw none of it. And that is one reason she has taken part in a compelling true crime series Red Flag, which explores how toxic relationships unfold.

‘There were plenty of red flags from the beginning – it’s just I was totally naive to them. I’d never been exposed to somebody like that,’ she says now. ‘I was hugely professionally successful, but it was only once I was fully outside the relationship that I could comprehend the scope of what had happened. The person I had fallen in love with was a total sham. He didn’t exist.’

Certainly, the man Kathryn fell for in 2013 seemed about as far removed from the stereotype of an abuser as she could imagine.

Then 47 and flying high at work, she was alone for the first time following the break-up of her marriage to her childhood sweetheart, the father of her two children, Thomas, now 36, and 32-year-old Holly.

‘I’d had over 30 years of a loving, stable relationship, having been brought up in a loving middle-class family. That’s what I knew,’ she says. ‘So being alone was new territory.’

After venturing on to an internet dating site, she quickly found Mark – his surname cannot be given for legal reasons – a handsome, blue-eyed, 6ft 4in property developer whose profile was as compelling as his appearance.

‘He said he had written poetry and seemed very thoughtful about life,’ she says.

The pair met at a local pub and hit it off immediately. ‘We chatted for over four hours. I thought he was a gentleman. He really sold himself on that fact and I had no reason to doubt him.’

And certainly, at first, that seemed to be the case. Mark, like Kathryn a divorcee, opened car doors, held her hand and made sure that when they walked together, he was always on the outside of the pavement. A motorbike-riding rugby player, he was also ‘alpha off the scale’.

‘I thought he was going to protect me in life,’ she says.

Their romance developed quickly: within six months Mark had suggested he move into Kathryn’s stunning detached home on a village green near Sevenoaks, Kent.

There had, she now admits, been warning signs by then that Mark was not always a ‘gentleman’. ‘He had terrible road rage. I didn’t like those behaviours, but I loved him so much I just ignored them.’

Nor did Mark appear to have any money, despite his apparent professional success.

‘He had a big house, but he was in arrears on his mortgage, owed the taxman and drove an old car. So from very early on I was bailing him out,’ says Kathryn.

There were tensions, too, with her children, then 23 and 19 – and in Holly’s case still living at home, while her brother was at university – who were unconvinced by the sudden arrival of Mark into their mother’s life. ‘They worried things were moving too fast, but whenever they complained, I saw it as them getting in the way of my happiness,’ she admits.

‘Mark was on his best behaviour with them at first, but it didn’t take long for situations to escalate.

‘When Tom was home he and Mark were soon at loggerheads, and he would complain incessantly about Holly, saying she was lazy and took me for granted.

‘Looking back, he was trying to drive a wedge between us.’

By now, however, Kathryn had fallen deeply in love. ‘He made me feel like a princess. I thought we were a match made in heaven. I was deeply in love with him, and I thought he genuinely cared for and loved me, too.’

And so when, in November, just ten months after they had met, Mark proposed – getting down on one knee in front of an entire restaurant and serenading Kathryn with the Elvis hit The Wonder of You – she didn’t hesitate to accept.

‘It felt like a fairy tale,’ she says.

Only after she had accepted his proposal did Mark confide that he had a criminal record for violence.

‘He painted it as a rugby accident. I later found out it was much more serious and the man’s jaw had to be wired back together.

‘At the time, I thought it was wonderful that he had chosen to be honest with me.’

Nonetheless, the fairy tale was already developing a darker underbelly. In 2014, Mark lost his temper with Kathryn for the first time, after their car was upended following a blown tyre late at night. He had been driving, yet he blamed her.

‘I had hurt my ankle, but Mark was so furious that he insisted I walk home in the dark even though I was in agony. He said I had forced him to drive, and it wouldn’t have happened if I’d driven home as originally planned – even though he was the one who had insisted on driving.’

In her shock, she rationalised it. ‘I even persuaded myself that he was right, that it was my fault, even though deep down I was sickened by the episode.’

Meanwhile, Mark was creating further distance between Kathryn and her children. By now, the couple had made the decision to sell Kathryn’s home and move into Mark’s home along with Holly – and he quickly made Holly feel unwelcome.

‘He would continually undermine her, telling me I wasn’t doing her any favours and she needed to become more independent,’ Kathryn recalls. ‘There were lots of arguments between them.’

So when Mark suggested buying a mobile home for Holly in his garden, Kathryn acquiesced, despite her daughter’s protestations.

‘He presented it as a good thing – she would have her own space, take on some responsibility and it would ease the tension.’

She pauses. ‘It is one of the things I feel the most sadness about, that I allowed him to affect my relationship with my children.’

Yet at the time she couldn’t see it, not even when her son refused to attend her wedding in April 2015, saying he could not in all conscience watch his mother marry a man he couldn’t abide. One of her close friends refused to attend, too.

‘You tell yourself that it’s on them, not you,’ she says quietly.

Marriage, though, heralded a new, more sinister chapter in their relationship.

‘Once we were married, that’s when I really started to see the darker side,’ Kathryn says. ‘Mark would lose his temper, throw things. On one occasion he smashed up a chair and threw it across the kitchen.’

A particular flashpoint was the fact that Kathryn had been made redundant. ‘Mark went crazy, screaming at me that I wasn’t going to just live off him,’ she says. ‘At that point, though, he hadn’t been physically violent with me.’

That changed a few months after the wedding when, following an argument, Mark picked his new bride up by the neck and dragged her out of the house, screaming abuse as he flung her across the threshold over which, only months earlier, he had romantically carried her.

‘I was fighting to stay inside, and he threw me on the ground then closed and slammed the door behind me, leaving me locked out barefoot in the pouring rain,’ she says. ‘I remember crawling along the ground, thinking: if people from the office could see me now.’

Bruised and frightened, Kathryn sought sanctuary in Holly’s mobile home before both took refuge at a neighbour’s house and called the police.

‘The kids could not believe it,’ she admits. ‘But from my perspective, I’d put everything into that relationship. I’d sold my house and used the proceeds to pay off the mortgage on his house. I was rationalising it, thinking, “I’m throwing away my whole life over this one argument.”

‘Part of me thought “I’ve fixed every problem in the world in my job – I can fix this”.’

Instead, it was the start of a terrible cycle. ‘There were long periods where he would shower me with wonderful holidays and experiences,’ she says. ‘I told myself this here was the lovely guy I married.’

But in 2021, after returning from a night out with friends, Kathryn said something that angered her husband.

‘He started shouting. I put my arm out to push him away because he was shouting into my face and he snapped,’ she says quietly. ‘He hit me with everything he had in him. It wasn’t just one punch; it was a sustained attack. He hit me over and over again in the nose.’

Yet astonishingly, Kathryn did not call an ambulance or the police. Instead, she pushed her nose back into place as best she could, covered the bruises with make-up and carried on as normal.

‘Years later, when a surgeon properly reconstructed my nose, he said he’d only seen similar injuries once before, and that person was dead in A&E,’ she says.

‘Mark didn’t apologise – he never did. In fact, he said I had started it by “hitting” him first. And I knew if I called the police that would be it and I couldn’t face it. And in the middle of all of this he was still cradling me in bed at night and telling me he loved me.’

By 2023, the violence had become horrifyingly commonplace – so much so that her despairing daughter Holly told her that if she didn’t get away, she would end up dead.

Those words would ring in Kathryn’s ears just weeks later when, in April that year, following an argument over money, Mark launched his most horrific assault yet. ‘He dragged me from my bed and forced a full, open bottle of wine right down my throat as I was thrashing around trying to get away,’ she says.

As he marauded around the house smashing furniture and possessions, Kathryn desperately tried to summon help, messaging Holly and friends on her iPad and begging them to call the police.

‘When Mark saw what I’d done he attacked me again. I put my hand up to protect my face, so he punched me violently in my back and ribs. It was agony.’

Who knows what might have happened next had police not arrived, along with an ambulance? Mark was arrested and Kathryn taken to hospital, where nursing staff did a head CT scan but, astonishingly, failed to spot that she had a broken back and ribs and a bleed on her kidney.

‘The next day when I was still in agony my son took me to another hospital who did a full body scan and realised the extent of my injuries,’ she says.

Yet such was the astonishing grip Mark still exerted over her that, even then, Kathryn hesitated before agreeing to bring the force of the law down on him.

‘Luckily my children made me see sense,’ she says.

Mark was charged with one count of GBH and three of ABH – including for the attack in which he broke her nose – and remanded in custody until his trial that September.

When the case eventually came to court, Kathryn recalls Mark was ‘cocky beyond belief, laughing and smiling at his friends’.

A day into the trial, she was told Mark was willing to plead guilty to four counts of ABH if the more serious GBH charge was dropped.

‘It was made very clear that I should accept this,’ she says. ‘The CPS told me that he and his family were blaming me for the violence, that any trial would be very distressing and it would make little difference to his sentence. I felt I had little choice but to accept.

‘What horrified me is that I was promised he wouldn’t be bailed before sentencing – but he was.’

Finally, in April 2024, Mark was sentenced to two years in prison, although shockingly he was released on licence just five months later due to prison overcrowding, after serving a total of nine months.

Kathryn, who now runs her own risk management company and has written a book about her experiences she hopes to publish, has since had to take out a non-molestation order against him.

‘I have logged 110 separate incidents, from terrorising tenants at my rental properties to barricading the gates of my home. He was arrested at one point, but no further action was taken,’ she says.

Such is her ongoing fear of Mark – whom she divorced while he was behind bars – that she has a panic room and state-of-the-art security system at her home.

Yet she is also determined not to see herself as solely a victim, but to use what happened to her to help other women recognise the danger she herself could not see.

An ambassador for the Employers’ Initiative on Domestic Abuse, which works with organisations around the country to support employees affected by domestic abuse, she tells her story to challenge one of the most persistent myths: that women like her somehow cannot become victims.

‘I tell them: “This happened to a managing director at JP Morgan. If you think it’s not happening to people here, think again”,’ she says. ‘I’m a living, walking example of domestic abuse.’

All episodes of Paul C. Brunson: Red Flag are available now on U