Six members of a drugs gang jailed for up to six years for smuggling hashish from Pakistan to the Netherlands have been allowed to keep the proceeds because of public prosecution department failings.

Judges in Den Bosch on Tuesday said the gang could keep the cash because of negligence on the part of the public prosecutor in accessing the amount of money it wanted to claw back, local broadcaster Omroep Brabant reported.

This had called the legitimacy of the court into question, the judges said.

The public prosecution department had been trying for three years to claim millions of euros which the gang had made through the drugs trade but had failed to produce proper documentation or reports on how they calculated the amount, the court said.

The initial claim was for €37m but this was later revised down to €23m.

The public prosecutor had ‘been unwilling to put enough effort into carrying out an inventory of the criminals’ assets,’ the court said.

The leader of the gang was shot dead in 2012, shortly before the start of the criminal trial.