In the pre-internet age, it might never have occurred to Gavin Plumb to try to recruit accomplices for his depraved kidnap and rape plot.
It is not the sort of job someone could have placed an advert in the local paper for.
But with a swipe of his smartphone, and without having to even verify a telephone number or email address, the security guard could access hundreds of like-minded individuals who shared his sick appetites.
Jurors yesterday agreed that thousands of vile messages exchanged with other men online about abducting and raping Holly Willoughby amounted to more than just fantasy.
And the 37-year-old was unanimously convicted of soliciting murder, incitement to rape and incitement to kidnap the former This Morning host.
Mark Mulligan, with whom Gavin Plumb shared details of the plot to kidnap Holly Willoughby, dressed as He-Man. He used this picture on a dating site
Plumb’s hunting ground of choice when attempting to assemble a ‘crew’ to put his plan to snatch Ms Willoughby into motion was a messaging app named Kik.
Among the band of degenerates with whom he shared intimate details of the plot was a user named ‘Marc’.
The Mail can reveal that ‘Marc’ is a 49-year-old stalker from Dublin named Mark Mulligan, who was jailed for three-and-a-half years in 2014 after spending four years harassing a mother and saying he would ‘love to rape’ her three-year-old son.
Mulligan was also convicted of possessing and producing child pornography at Dublin Circuit Criminal Court.
Depraved messages he exchanged online about television presenters from Irish stations RTE and TV3 mirrored the conversations he would have with Plumb almost ten years later.
The pair exchanged thousands of messages, with Plumb telling his trial he felt they were forging a ‘real friendship’.
The Irish court heard Mulligan replied to a man who suggested snatching a child: ‘Mmmm, make him watch us kill his mum and dad and then kill him.’
Years later, when Plumb told him they would have to find somewhere remote to keep Ms Willoughby once they had abducted her, Mulligan responded: ‘Definitely in the middle of nowhere, so no one can hear her scream.’ He added: ‘Celebrities, they think they’re full of themselves, they need to be f***ing put into place.’
A police source confirmed the Irish Garda was investigating Mulligan, but he has not appeared before a court.
Despite his sinister exchanges on private forums and convictions for stalking and child pornography offences, Mulligan described himself on a dating website as a ‘genuinely good person, [a] good listener’.
Above a gallery of images including one in which he is dressed as muscle-bound hero He-Man, Mulligan tells prospective lovers who visit his PlentyOfFish profile that he is a 5ft 5ins Catholic non-smoker ‘with a few extra pounds’.
Mulligan’s contrasting conduct on these platforms illustrates the vast cultural gulfs that exist between different sites – all of which offer varying levels of anonymity and encryption.
On the surface, Kik, which was founded by a group of Canadian students in 2009, appears to have been an odd choice for Plumb to have used for his obsessive kidnap-gang recruitment drive.
Holly Willoughby at the National Television Awards in 2023
Unlike platforms commonly used by criminals such as Telegram, Kik does not offer end-to-end encryption – a system which means no third parties or law enforcement can access messages.
But Kik does offer something else: a space for people with interests too shocking to discuss in the real world to meet and speak freely.
DCI Greg Wood, the senior investigating Essex Police officer in Plumb’s case, said his violent language in the chatroom showed how comfortable he was in this environment.
‘He was clearly not bothered about encryption or being punished for what he was saying; he was open and overt and explicit throughout in terms of the threats and the language he was using,’ he said. ‘I just don’t think he cared.’
Plumb’s remarkably calm demeanour during cross-examination tallies with this notion that, thanks to a mindset warped by years of inhabiting the darker corners of the web, he saw nothing wrong with the vile language he used to discuss women.
After dropping into a swivel chair, having told the court he would be unable to stand in the witness box, Plumb faced a forensic grilling from Alison Morgan KC, for the prosecution.
Plumb insisted again and again that his language was nothing more than harmless ‘online chat’, and though he did articulate sorrow about prior offending, his body language suggested no embarrassment or remorse.
Asking about the 2008 kidnapping at knifepoint of two teenage girls in Woolworths, Ms Morgan demanded: ‘Do you disgust yourself when you think about this?’
Plumb responded that yes, he did – but the question failed to elicit so much as a shudder.
DCI Greg Wood from Essex Police reads a statement outside Chelmsford police station after Gavin Plumb was found guilty
This prompted a colleague in the press bench to note: ‘He doesn’t even realise this isn’t normal. He doesn’t know what normal is.’
For a short period after its 2010 launch, Kik looked to be winning the race to become the world’s most-used messaging app.
But when WhatsApp pulled away from all other rivals, it began morphing into a more niche platform for younger people and users with less mainstream interests.
Just six years after it went live, US detectives who arrested an American sex offender called Thomas Paul Keeler II found he was a member of more than 200 Kik groups with names such as ‘kidsnbabies’, all dedicated to trading child-abuse material.
Following the revelations, Kik promised to tighten its safety measures.
But DCI Wood said the company and other social-media platforms were completely failing to monitor dangerous chatrooms.
Plumb’s vile correspondence only came to light thanks to an undercover US police officer, known as David Nelson, who infiltrated a disturbing chatroom about kidnapping love interests named ‘Abduct Lovers’.
Plumb’s phone was seized upon his arrest and police retrieved thousands of sick messages with Mulligan and other users.
And the Mail can reveal that two of the three main groups in which Plumb operated are still live.
The Abduct Lovers group, where Plumb met Mulligan and discussed his Willoughby plot with other users, vanished from the platform only last weekend after it was named during the trial.
The group, which had a photo of a distressed blonde woman with a man’s hand covering her mouth as its profile image, was at capacity with 100 members.
But two other chatrooms dedicated to obsessive fans of Holly Willoughby in which Plumb was a prolific poster remain active and open to new members.
Just minutes after a reporter joined the Holly Willoughby Fans group, a user named Dave Brownz posted a Photoshopped pornographic image of the former This Morning presenter next to Spice Girl Emma Bunton.
This photo was followed by an avalanche of posts about Ms Willoughby that are too repulsive to publish.
Our reporter was ejected from another group frequented by Plumb named ‘Hollywilloughby1’ for failing to post any content about the television star.
‘This is a sneaky method that the admins of illicit groups use to keep undercover police and other unwanted members out of their chatrooms,’ says Jake Moore, global adviser at cybersecurity firm ESET.
The Kik group Abduct Lovers had 100 members before it vanished from the platform
‘Many forums only let people remain there if users continue to post the sort of material they are looking for. If members don’t, then they are swiftly ejected.’
The combination of minimal verification checks, easy access to illicit chatrooms and this policy of removing unwanted members has created a culture that emboldens sexual predators.
In just the first half of this year, a string of British sex offenders have been convicted of using the app to lure vulnerable targets.
Alfred Dempster, 57, from Wisbech, Cambridgeshire, was jailed in February after begging a user who he thought was an 11-year-old girl for explicit photos and pestering another decoy posing as a 14-year-old for sex.
Serial paedophile Matthew Lockwood, 47, from Chatham, Kent, was jailed in January after using the app to entice young boys into his flat with promises of cash, only to sexually abuse them.
In April, 26-year-old Stuart Evans, from Wrexham, was given an 18-month jail term suspended for two years after demanding sex from an undercover police officer posing as a 13-year-old girl on Kik.
Paedophile Stephen Grant, 44, from Romsey, Hampshire, used the app to groom young girls around the world, including in Australia, and was jailed for five years and nine months in May after admitting a string of offences.
Stuart Witham, 31, from Harrogate, tried to sell indecent images of children for Bitcoin and Amazon vouchers on Kik chatrooms and was jailed for two years in February.
And Stuart Brown, 42, from Co Durham, will be sentenced on July 23 after admitting having sexual conversations on the app with a girl he believed to have been 13.
Mr Moore said companies such as Kik very rarely bother to devote time and resources to monitor the content of their chatrooms.
‘Don’t be fooled into thinking that Kik Messenger is controlled or run by a serious organisation like Meta; it could just be a small group of people who maintain it and have no idea of the sort of material on there,’ he added.
And DCI Wood pointed at the ease with which the undercover US officer was able to find and enter a group dedicated to the abduction of female celebrities.
‘If he could find it that easily then surely the social media companies hosting it can,’ he said.
‘And if they can, why aren’t they shutting it down?
‘What is going to be going on in a group called Abduct Lovers other than violent and misogynistic behaviour towards women and girls? Nothing. So why do we allow it?
‘If you look at the language, the violence and misogyny Gavin Plumb used in his conversations with Mark [Mulligan] and David Nelson – if those conversations were happening in the street, it would be a matter of seconds before someone challenged him, stood up to him, reported it and called the police.
‘That shouldn’t be any different online.’
Plumb was able to lurk in the web’s darkest corners and plot an attack that would take place in the real world.
‘These spaces are vast and cover the entire globe,’ DCI Wood said. ‘It’s impossible to know how many others there might be like him.
‘Unfortunately there isn’t an undercover officer in every sinister chatroom.’
Kik has been contacted for comment.