The First Division Association, which represents senior civil servants, negotiated with the UK government for the increase.

Other Crown Prosecution Service (CPS) professionals and senior managers will be given an eight per cent rise.

The higher pay will be made over two years and is part of a deal that will also see pay ranges narrowed and a 13.5 per cent increase in the department’s overtime rates.

Steven Littlewood, the association’s national officer, said the increase was a “well overdue reward for long-serving staff, who have been trapped in the lower ends of pay ranges for years”.

He added: “We must ensure that our criminal justice system remains a world class institution. We can’t allow justice to be devalued.”

Chris Henley QC, chairman of the Criminal Bar Association, said that while prosecutors and CPS staff would benefit from the deal, self-employed barristers who dealt with the most difficult prosecution cases were paid less than they were 20 years ago.

“Fees were static until 2012 and were then cut. Not even inflationary increases have been allowed. Nothing,” he said.

Mr Henley told The Brief: “The current fee structure completely fails to pay for much of the work modern criminal trials require, and there is no fee for the second day of any crown court trial.

“Hourly rates often work out at less than minimum wage levels. There is no flexi-working, sick pay, pension provision or passing the buck for the barristers.”

He said barristers’ commitment, professionalism and ethical conduct had been abused by the government.

“Their quiet fury will soon become publicly deafening if immediate action is not taken. We have asked politely and been ignored for long enough,” he said.