The chaos that has descended on the translation facilities available to Britain's courtrooms is an object lesson in how not to privatise a public service. Court officials have had to scramble to find qualified interpreters at short notice. There has been a sharp rise in delayed and abandoned trials. Individuals have been kept needlessly in jail on remand. And the quality of interpreters has at times been appalling. All this is contained in a withering assessment of the new system by the Public Accounts Committee.

The old system, under which courts booked interpreters autonomously, needed reform. It was wasteful of both money and time, though at least it worked. But government ministers decided that a centralised system would offer better quality, greater efficiency and lower costs. Perhaps so, but not the way the Ministry of Justice organised things. In January 2012, it handed the job to a company called ALS-Capita, without carrying out due diligence.

It did not, for instance, check basics such as how many interpreters were needed or in what languages. It failed to check that ALS could supply the 1,200 specialist staff needed. (Only 280 were available when the system went live.) It ignored the views of existing interpreters who said they would not work at rates which, docked of travel and waiting time, amounted to less than the minimum wage.

It failed to do a proper pilot study and rolled the new system out nationally all at once. It allowed ALS to be its own auditor, reporting its own performance figures. And it did not check that the new staff were competent or security cleared; in the event, many had merely registered an interest on the company's website – one person had even registered their pet dog.

As the debacle over the West Coast Main Line demonstrated, privatisation cannot work if companies are allowed to get away with over-promising and under-delivering. Ministers are now saying there has been some improvement in performance, but the system is still struggling and in need of a major review.