A trial at a London court has collapsed after an interpreter mistakenly gave the wrong evidence.
A Romanian defendant giving evidence at Snaresbrook Crown Court said the claimant had "beaten them" but the interpreter said "bitten".
The mistake came to light once the prosecution questioned the defendant. The judge has now ordered a retrial.
It comes as a new contract privatising court translation services in England and Wales has come into force.
Defence solicitor Dhaneshwar Sharma said the interpreter from Applied Language Solutions told the court she realised she had made a mistake but had kept quiet about it.
When the prosecution cross-examined the defendant on Friday, towards the end of the four-day trial for burglary, they asked for evidence of the defendant being bitten.
The defendant then said they had been "beaten".
Mr Sharma said it was bad that a re-trial had to take place as not only had the victim had to recover from the experience, but they would now have to go through the alleged incident for a third time, having already given evidence at this week's trial.
The retrial could cost £25,000.
The Crown Prosecution Service said a retrial had been ordered after the judge said the collapse of the trial was due to the interpreter. At a hearing next week the court will decide on a date for the retrial.
The National Register of Public Service Interpreters has said 61% of its members have boycotted the ASL contract because of poor pay and working conditions.
The Professional Interpreters Alliance said this had led to incompetent interpreters being used in courts.
Previously interpreters 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a flat fee of £85, a quarter-hourly rate after three hours, and were paid for travel time and expenses - but this has been replaced by hourly fees in three tiers of £16, £20 and £22 with no travel payments and reduced expenses.
The company awarded the contract - Applied Language Solutions - has promised to cut the annual £60m translation bill by a third.
A Ministry of Justice spokesperson said: "There have been an unacceptable number of problems in the first weeks of the contract and we have asked the contractor to take urgent steps to improve performance.
"They have put measures in place to resolve these issues and we have already seen a marked improvement."
A spokeswoman for ALS - recently bought by the outsourcing firm Capita - said although it could not comment on individual cases, any complaints received would be "investigated thoroughly".
The spokeswoman said interpreters could then either be removed from the register, reinstated or provided with further training.