The Dutch royal family receives ‘generous’ financial compensation for the tax they pay over their income from assets, according to RTL Nieuws.

Family members have had to pay tax on their income from shares and savings since 1973. However, RTL has found secret documents showing that queen Juliana was given a higher allowance by the state to compensate her for the tax payments.

The broadcaster says it is impossible to calculate how much the Oranjes have benefited from the extra payment, but says in the 1970s, the compensation was at least 150,000 guilders a year.

King Willem-Alexander will get a tax-free allowance of €5.5m in 2017, calculated on the basis of the 1973 ruling, RTL said.

Currently, members of the royal family receive a tax-free salary and are not required to pay gift or inheritance tax.

A year ago, prime minister Mark Rutte defended the royals’ tax free status, arguing that ‘a deal is a deal’.

Much of their money is in foundations, which do not pay tax. The taxpayer also picks up the bill for security, rebuilding palaces and the former queen’s yacht De Groene Draeck.  The Dutch royal family is considered to be the most expensive in Europe, and costs the taxpayer some €40m a year, excluding security.