Richard Arcari was a civil servant working for the Department for Environment, Food and Rural Affairs (Defra) when a routine security check uncovered indecent images of children.
He was sacked in October 2018, as a police investigation continued, but went on to work in the press offices of Imperial College Healthcare NHS Trust and the Zoological Society of London.
Arcari was also employed by the Royal Borough of Kensington and Chelsea, in a role that his LinkedIn profile claimed to include “looking after media and community engagement post Grenfell”.
The 37-year-old was jailed for three-and-a-half years on Tuesday after admitting 22 charges.
Arcari pleaded guilty to making indecent images of children, possessing extreme pornographic images, possessing class-A drugs and intentionally encouraging or assisting the commission of an offence.
The charges included offences of possessing extreme pornography depicting “sexual interference with a corpse” and bestiality.
The defendant, of Kings Avenue in Clapham, had more than 700 images of the most serious category, and almost 1,000 other pictures and videos.
A judge at Inner London Crown Court ruled that he would be put on the sex offenders register indefinitely and given a sexual harm prevention order restricting his use of the internet.
Arcari was first arrested in February 2017, when the Metropolitan Police received intelligence that he had watched an online video of a man raping a boy and offered to swap videos with other paedophiles.
Officers found hundreds of child abuse videos on Arcari's iPad but bailed him. He was working as a senior press officer for the University of Surrey at the time.
In March 2018, the National Crime Agency (NCA) arrested Arcari after he was linked to the username “FitPrvUK” in an online conferencing room where child abuse was streamed.
By that time Arcari, then a civil servant working in Defra’s press office, had acquired a new laptop that also contained hundreds of abuse images.
He told investigators that he had visited the conferencing room to watch male pornography, but could not remember what he had viewed or streamed because of his use of crystal meth.
Little over a fortnight later, NCA officers searched his home again after discovering he was still using the room under a new name, and found another laptop and phone containing child sex abuse material.
Then, in September 2018, Defra informed the NCA that they had discovered Arcari’s use of an unauthorised memory stick with “file titles indicative of indecent images of children” during a routine security check.
Yet more child abuse content was found on the USB stick and work laptop.
A spokesperson for Defra said Arcari had passed the required pre-employment vetting in late 2017, including a criminal-record check, because he had not yet been charged with an offence.
He was suspended by the government department on 7 September 2018 and sacked on 30 October that year.
The Independent asked Arcari’s subsequent employers how he came to be hired during the NCA investigation, and following his dismissal by Defra.
A spokesperson for Imperial College Healthcare NHS Trust said he worked there for a matter of weeks and was based in a corporate building where no patient services were delivered.
“We are extremely concerned about what we have learnt today about Arcari,” a statement added.
“He worked for the trust in a temporary role for a few weeks in August. We have begun an immediate review to understand how his full background did not come to light during employment checks.”
The Zoological Society of London, which operates the capital’s zoo, said he had been employed through an agency for a temporary, office-based role between September and November 2018.
A Kensington and Chelsea Council spokesperson said: “He was employed by an external agency and worked at the council for two weeks, in an office-based role, before the council chose to terminate his contract. We have contacted the relevant agency and asked for an urgent explanation on the checks they have in place and how this could have happened."
On his LinkedIn page, Arcari described himself as having nine years of experience in communications and a “good knack at working with ‘set in their way’ colleagues to tease out good news stories and angles that they may not see”.
Graham Ellis, NCA operations manager, said: “The evidence showed Arcari was visiting online conference rooms to watch child abuse from as long ago as November 2015.
“Even when he had been arrested and was on bail he continued to offend.
“Every time footage is replayed or an image reshared, that child is revictimised."
The case came as the NCA warned that the scale and severity of offending against children is worsening.
The NCA and British police arrest about 500 suspected paedophiles and safeguard about 700 children every month, and have called for help from technology firms to combat the rise in abuse.