Dozens of magistrates have resigned in protest over court charges that they claim encourage the innocent to plead guilty and will never be collected.

Former justice secretary, Chris Grayling, introduced the fees, which came into effect in April, as a means of ensuring that those convicted of crimes contribute towards the cost of running the courts.

In the magistrates’ court, the fees range from £150 for a defendant who pleads guilty to a summary offence, up to £1,000 for anyone convicted of an either way offence. In the Crown court, the fees range from £900 for a guilty plea up to £1,200 for conviction after trial.

They are not means tested and must be paid on top of any fines, compensation orders and the victim surcharge.

Chairman of the Magistrates’ Association, Richard Monkhouse, estimated that “over 30” magistrates had resigned since the charges were introduced, but said the number could be “much higher”.

He said: “During my time on the Bench, I have rarely seen an issue strike such a deep chord with magistrates. They have very real concerns about the fairness of the charge and its impact on pleas in court, which frankly goes to the very heart of justice”.

He questioned whether most would ever be paid due to poor collection rates and defendants’ lack of means to pay.

The association has called for an urgent review with a view to granting judges and magistrates discretion over its application, including means testing.

The Howard League for Penal Reform, which is campaigning for the charges to be scrapped, has highlighted the disproportionate impact that they are having on poor and homeless people charged with trivial, low value offences.

Its chief executive, Frances Crook, said: “Up and down the country, people are being brought to court for minor misdemeanours and being ordered to pay a mandatory charge regardless of their circumstances.”

Mark Fenhalls QC, Chairman of the Criminal Bar Association, said the charge is “deeply unjust” and he suggested that magistrates and judges should be allowed to take into account an individual’s means.

A Ministry of Justice spokesperson said: “It is right that convicted adult offenders who use our criminal courts should pay towards the cost of running them.

“The introduction of this charge makes it possible to recover some of the costs of the criminal courts from these offenders, therefore reducing the burden on taxpayers.”

The MoJ will review the charge after three years, but has not indicated that it will bring that action forward.