The government is hoping to save £18m a year by changing how interpreters are provided for court hearings - but it is said the new system is causing chaos and costly delays.
A suspect charged with perverting the course of justice is told they are accused of being a pervert. Another is told that being charged means they have to give the police money. Two incidents cited by those opposed to the new system.
Courts in England and Wales previously hired freelance interpreters from a national register. Now they are provided by a single agency, Applied Language Solutions (ALS), which has promised to cut the annual £60m translation bill by a third.
While the company says despite some "teething troubles" it is operating well, 60% of the 2,300 of those on the National Register of Public Service Interpreters are refusing to work for it after their pay was slashed.
Previously they received a flat fee of £85, a quarter-hourly rate after three hours, and were paid for travel time and expenses - but this has been replaced by hourly fees in three tiers of £16, £20 and £22 plus no travel time and reduced expenses.
In some cases, an interpreter's pay would be halved for the same three hours of work, while those who used to travel long distances to assignments could be out of pocket.
For example, one Lithuanian interpreter who regularly travelled to Devon from Surrey and used to get £246 for a day's shift would now be £65 down after travel costs.
Some fear the change could have more damaging consequences. The interpreters' membership body, the Professional Interpreters Alliance, says the boycott is forcing ALS to employ people with little experience of the legal system.
"We are already hearing horror stories from all over the country. Being a court interpreter is a specialised and difficult job. You have to be accurate as people's liberty is at stake," director Madeleine Lee said.
There is a huge demand for interpreters to help defendants, witnesses and victims understand the legal system.
John Storer, a solicitor for a firm in Boston, Lincolnshire, says 20% of the local population are migrant workers, meaning 20/25% of his clients do not speak English. "We rely on interpreters for cases from murder to motoring offences," he said.
Since ALS took over at the beginning of February, solicitors, translators and magistrates across England and Wales have reported numerous cases of interpreters failing to attend, not speaking the right language and not accurately translating proceedings.
In one case, a Lithuanian man was in custody for theft on a Monday, but as no interpreter was present he was remanded without a bail application as his solicitor simply could not get any information from him. He was eventually dealt with on a third occasion, a week later.
One of the PIA interpreters listened to part of the interpreting during the cross-examination of the defendant and the closing speeches in a case at a crown court, which they described as "very vague and incomplete".
They reported: "I would say one fifth of what was being said in court was interpreted to the defendant. At one stage the interpreter, instead of interpreting what the judge was saying, was telling the defendant that she thought the judge was nice and sympathetic towards the defendant's case."
'Bound to be appeals'
Richard Bristow, chair of the West London bench of magistrates, said the cost of sending defendants back to custody when interpreters failed to show could mean the change was a false economy.
"I had a case where the interpreter didn't turn up and I was stuck between a rock and a hard place. It's not right to proceed when the chap doesn't really understand what's going on, but it's also not very just or fair on him to put it off for another day and leave him sitting in a cell overnight while we get an interpreter," he said.
"On top of that there are all the other agencies, because it's not just the defendant, it's the police, the probation, the defence, the CPS; they are all incurring costs because there's no interpreter there."
Rebecca Niblock, a solicitor specialising in extradition cases, said it could pose problems for the justice system further down the line.
"There is inevitably bound to be appeals as it's fundamental that people understand what is said, not just in court but in speaking to their lawyers. It's not just their presence that is required but their input, whether they are pleading guilty or not guilty - if there's any uncertainty over what's said that leaves the door open to appeals."
Mr Storer said his firm would employ freelance interpreters using Legal Aid money if it was not satisfied with the standard of ALS interpreters.
"Good interpreters save money as can speed things up, they are fully aware of the legal process, they know exactly what to do and what's expected of them and they just get things done," he said.
Mike Jones, Chairman of the Criminal Law Solicitors' Association, said he was concerned by what his members were telling him.
"Accurate interpretation is absolutely essential to the operation of the criminal justice system in the police station, magistrates' court and crown court," he said.
The Ministry of Justice said it was closely monitoring the operation of the new contract and working with the contractor to ensure it worked as effectively as possible.
An ALS spokeswoman said 3,000 interpreters are registered with the company, who are then vetted for their qualifications and undergo independent assessment.
"The service was rolled out nationally less than two weeks ago and has been operating well, although there have, inevitably, been some teething troubles," she said.
"We are closely monitoring the service, will investigate any complaints made about the system and make changes and improvements as necessary. Assigning qualified and experienced linguists to assignments and insisting on continuous professional development, while reducing operational inefficiencies, remains the focus of our service."