Security has been stepped up around the heir to the throne, princess Amalia, and prime minister Mark Rutte because of concerns they could be targeted by organised criminals, the Telegraaf reported.

Amalia has delayed moving in to her student accommodation in Amsterdam, where she is studying Politics, Psychology, Law and Economics, after her name and the prime minister’s cropped up in intercepted messages, the newspaper said on Saturday.

The government information service Rijksvoorlichtingsdienst said it did not comment on security arrangements, but justice minister Dilan Yesilgöz told WNL op Zondag that there were ‘very serious’ threats in general from the underworld against politicians, public figures and journalists.

Yesilgöz said she was working on plans for a stricter detention regime with tighter supervision for ‘exceptional category’ criminals such as drugs gang bosses.

Security guards at the high-security prison in Vught also raised the alarm about correspondence between Ridouan Taghi, who is currently on trial accused of being the head of a gang that carried out six gangland assassinations in 18 months, and Mohammed Bouyeri, the murderer of film-maker Theo van Gogh.

Taghi’s lawyer Thomas van der Horst confirmed that the two had exchanged letters, pointing out that correspondence between inmates was not forbidden. The Telegraaf said the letters contained citations from the Koran, but Van der Horst denounced what he called a campaign by the media to ‘generate suspicion’.

‘The number of letters in more than a year can be counted on both hands, and only four of them came from my client,’ he said.