Justice committee MPs revealed yesterday that ministers' "shambolic" outsourcing of interpreters had caused cases to collapse and other court chaos.
In one case an unqualified man stood in for his wife as an interpreter in a murder trial.
MPs slammed the Ministry of Justice for ignoring warnings that it was sacrificing the quality of the service when it handed the contract to Applied Language Solutions (ALS), now renamed and part of bungling privateer Capita.
It has led to some cases being held up and others collapsing completely.
Interpreters have been asked to travel to far-away courts and paid badly, while there have been serious cases of underqualified translators making serious mistakes.
MPs were told that one interpreter mistranslated a defendant's statement, making a jury seriously doubt their evidence.
The committee said there was "clear potential for problems" with ALS's ability to fulfil the contract, but neither the firm nor the Ministry of Justice had taken action.
It added that this was a particular concern as the ministry gets set to farm out vital probation work to privateers.
Committe chairman Sir Alan Beith said: "The ministry's handling of the outsourcing of court interpreting services has been nothing short of shambolic."
Justice Minister Helen Grant claimed that, while there had been "significant" issues at the start of the contract, the department had seen dramatic improvements after taking "swift and robust action."