A prison exercise area was described as an "execution yard" in a handbook for Russian inmates, inspectors said yesterday.
The translation error in the information booklet for Russian-speaking prisoners at Lincoln Prison was highlighted by inspectors after an unannounced visit in May.
Inspectors suggested checking the accuracy of any translations in the future.
The report, published by the Chief Inspector of Prisons, Nick Hardwick, said: "Staff were concerned that some translations were not entirely accurate, one example being a Russian handbook which had translated 'exercise yard' as 'execution yard'."
The report added that, in future, "the accuracy of translated material should be verified".