This was the main reason why they went ahead with the prosecution of Tabak regarding porn images
David Bartlett, prosecuting, said it was important that Tabak was legally recognised as a convicted sexual offender.
Mr Bartlett said the majority of images related to two teenage girls of "relative maturity" and were in the least serious category.
"But some of the most serious category are not, they are of pre-pubescent girls," he added. Although he's serving a minimum tariff of 20 years' imprisonment, we felt it was crucial Tabak was brought to justice for possessing indecent images of children, so the full nature of Tabak's offending is on record."
Mr Moss said the conviction meant an "extensive range" of protective measure could be put in place to manage his behaviour and protect those at risk.
It will have a direct impact on how he is managed in prison and how he is monitored and managed upon his release, he added.
It's possible he may return to the Netherlands following release, so it's crucial the Dutch authorities are aware of the risks he poses," Mr Moss added.
"This could only have been guaranteed if a relevant conviction relating to a sexual interest in children were secured.