I was first victim of 35-stone mummy's boy who wanted to rape and murder Holly Willoughby. He smelled so bad I had to use air freshener to work with him. Then he forced me into a back room, tied me up and pulled out a knife...

Pushed face-first against a wall, 16-year-old Emma Ashby had every reason to fear the worst as her hands were roughly bound behind her back. Seconds earlier, a male colleague had pulled a 6in knife on Emma and her best friend in the deserted stockroom above the Woolworths in Harlow, Essex, where they all worked.

While the girls had initially thought Gavin Plumb was playing a joke, it quickly became clear his intention was sinister.

They were terrified as, breathing heavily and sweating profusely, he began to tie them up.

'All I was thinking was, 'Do exactly what he wants,' ' Emma recalls. 'Was he tying me up so he could potentially rape me? He had a knife. I remember saying to myself, 'Even if it is something sexual, you have got to do it.' '

Thankfully, just as Plumb prepared to gag Emma's mouth with tape, her friend Louise, also 16, made a break for it.

As the obese Plumb lumbered after Louise, Emma took her chance and rushed to the exit.

Desperately attempting to free her hands from the tape as she ran, she had to stay calm enough to tap a code into the locked door before she could get downstairs to the other staff – and safety.

Emma managed to release the door and raised the alarm.

'I was shouting and screaming as I got to the shop floor,' she says. 'They could see me running, crying and screaming, 'Gavin just pulled a knife on us and Louise is still up there!' '

Thankfully, Louise was rescued and Plumb was arrested.

In the 15 years since, Emma has never forgotten the nightmarish events of that evening in December 2008, though she has tried to put them behind her.

The following year Plumb was jailed for his attack on the girls, and when he emerged from prison after serving half of a 32-month sentence, all that Emma could do was hope that their paths would never again cross in Harlow, where they both lived.

But all those buried memories came flooding back in the autumn after reading about a plot to kidnap the television presenter Holly Willoughby. 'I remember googling it and seeing the name of the person arrested,' Emma recalls.

Now a 32-year-old mother-of-three, who works as an account manager for an events company, she has bravely spoken for the first time about her ordeal in an exclusive interview with The Mail on Sunday.

After reading about the plot to kidnap Ms Willoughby, she says she immediately phoned her mum and said: 'You know Gavin…' and her mum replied: 'It's him, isn't it?' She adds: 'I didn't even have to say what had happened.'

It brought home to her how lucky her escape from Plumb had been.

Her mum texted her, saying: 'It's scary to think what would have happened if you hadn't run.'

Emma closely followed Plumb's trial at Chelmsford Crown Court – the same court where he pleaded guilty all those years ago to falsely imprisoning her and her friend – where last week he was found guilty of plotting to kidnap, rape and murder Ms Willoughby.

In his defence, Plumb, 37, insisted that the plot was simply an online 'fantasy', never to be acted out in real life.

But Emma is in no doubt that the threat posed to Ms Willoughby was just as real as the terrifying ordeal she and her friend experienced at his hands.

'It's so scary to think what he would have been capable of if Louise hadn't run… if I had been on my own,' says Emma. 'Thank God I got away. He is 100 per cent dangerous and should be locked up for a very long time.'

The incident involving Emma wasn't Plumb's first brush with the law. The previous year he had been convicted of posing as a policeman and attempting to kidnap two Ryanair stewardesses from a train.

'He might say that it is fantasy to him, but he has done things like this in the past,' says Emma. 'Tying people up, dressing as a person in power... he has actually carried them out.'

In both incidents, Emma points out, there was considerable planning. In her case, as well as equipping himself with a knife, rope and tape, Plumb had asked to switch shifts so he was working with her. However, he was unaware that on that night she would have a friend with her.

For Emma, the daughter of a sales executive, the Woolworths job was her first taste of grown-up life. Having turned 16, she started working evenings and weekends while studying childcare at college. Plumb, aged 21 and seriously overweight, began working there on the same day.

Emma remembers them training together. 'We'd chat, like colleagues, but we weren't friends.'

Emma, who is just over 5ft tall, remembers Plumb's considerable bulk and that his body odour was so bad that managers put air fresheners in his till area.

As the busy run-up to Christmas approached, Emma arranged for her best friend, Louise, to start shifts, too.

On the evening of December 11, 2008, they were working together after closing time to restock the shelves. The friends grabbed a couple of Santa hats before heading to the cavernous stockroom, dancing to the carols blasting over the loudspeakers. As Emma puts it: 'We were just two teenagers loving life.'

She recalls how they were restocking the confectionery department and went to the stockroom to get some cans of drink. But because they were heavy, they looked for someone to help. Spotting Plumb, they asked if he could lend a hand.

'But instead of getting the boxes down, he pulled out a kitchen knife from his pocket and held it at both of us and said, 'Get to the back of the stockroom!' ' Stunned, the girls looked at each other. Emma recalls: 'We just looked at him and laughed – as if to say, funny joke.' But Plumb was not joking.

'He said it again, but more angrily, with more force, almost shouting, 'Get to the back of the stockroom now!' We were terrified, ran to the back of the stockroom and stood facing him with our backs against the wall.

'He pulled some rope out of his pocket but it was all tangled. I remember him saying 'f*** it' because he couldn't untangle it, so he pulled tape out of his pocket –like brown packaging tape.'

Now utterly petrified, the friends' ordeal was about to take an even more sinister turn. 'He shouted at us, 'Turn round and face the wall!' ' Emma says. Realising that Plumb was deadly serious, the girls turned around. She says he then said: 'Put your hands behind your back.'

Next he started tightly taping Emma's hands together behind her back. She says: 'When I was facing the wall, there was a tiny gap in the floor that I could see through to my colleagues below, by the tills, talking. When he'd finished taping me, he told me to turn back round and I assume he was going to put some tape across my mouth. But before he could get any more tape off, Louise ran.'

Heartstoppingly, because she was unfamiliar with the store, Louise ran in the wrong direction.

Plumb went after her, giving Emma the opportunity to head for the exit. 'I managed to get my hands free as I ran,' she says. 'I typed the code number into the keypad by the door, turning the handle and getting out.'

After Emma raised the alarm, two male managers rushed upstairs, returning soon after with an equally distraught Louise.

When the police arrived, Plumb tried to pretend that nothing had happened and had returned to where he had been working beforehand, surreptitiously replacing the knife where he had got it from – a knife-block in the kitchen section of the storeroom. Emma says that the officers found the block of knives out of its packaging, so they knew which one Plumb had taken.

She recalls seeing the Santa hats that she and Louise had been wearing, still on the floor at the back of the stockroom.

In the following weeks, Emma learned about Plumb's previous conviction for attempting to kidnap the Ryanair stewardesses in 2006. She struggles to understand how he then got a job at Woolworths, where he was dealing with children and other members of the public.

Given that Woolworths closed down shortly after the incident, she'll never know the answer.

In the end, Emma did not have to give evidence in court after Plumb admitted two charges of false imprisonment and one of battery, for tying her up.

But she was present when he was sentenced to 32 months in prison, sitting in the waiting room with her parents, opposite Plumb's mother and stepfather, and she remembers her sense of relief when he was jailed.

In the immediate aftermath of the incident, she remembers how scared she felt whenever she had to go back up to the stockroom at work, refusing to go alone.

But what shook her the most was when, shortly before Plumb was released from prison, she was visited by a police liaison officer. As part of his sentence, Plumb had a restraining order stopping him from getting in touch with Emma.

She says the officer gave her their number and told her to call if ever she saw Plumb while out or if she felt unsafe. But Emma now says: 'That almost made me feel worse, because it was scary thinking I could bump into him.'

Fortunately, she never did. But following his arrest over Ms Willoughby the police contacted her again to ask if she'd be willing to make a statement. She duly gave one, but in the end it was not read out in the court.

Following a legal ruling prior to the start of the hearing, the judge allowed the jury to be made aware of Plumb's previous convictions.

Plumb was questioned about them in court and, outrageously, claimed the Woolworths incident was a 'cry for help' – that he'd been in a toxic relationship and saw incarceration as preferable to staying with his partner. Asked to recall what it felt like when he put the tape around Emma's wrist, he said: 'I was scared.'

Understandably, Emma says: 'How shocking that he could say that. How does he think I felt – a 16-year-old girl just out of school?'

Now with three young children of her own, the thought of a man threatening them with a knife terrifies Emma.

She and Plumb both still live in Harlow and she has always been concerned about bumping into him, but she is not deterred.

'I'm speaking out for the sake of awareness. He should be sent down because, if not, I dread to think what he could do next.

'He might claim that Holly Willoughby is fantasy to him but, as I know first-hand, he has done things like this in the past.'

The peace of mind that Plumb's conviction has given Emma is palpable. 'He deserves a lengthy sentence for what he put Holly through, for what he put me and others through. It's a great relief to know he'll be sent to prison and unable to ruin anyone else's life.'

Yet, one of Emma's remaining concerns is what Plumb was doing in the period between his arrest for the offence against her in 2008 and his arrest in 2023.

'We just don't know what he was doing in that period,' she says.

Given Emma knows all too well what Plumb is capable of, it's a deeply worrying thought.