Swansea Council sent an email to its in-house translations service to have a road sign - 'No entry for heavy goods vehicles. Residential site only' - translated into Welsh.
The only problem was that the Welsh translator wasn't in at the time. An automated email response was sent to council officials who believed it was exactly what they needed.
But in fact it stated: 'I am not in the office at the moment. Send any work to be translated.'
Unaware of the real meaning of the message, authorities had it printed on the road sign under the English.
The council has since taken down the sign, which barred lorries from a road near an Asda supermarket, after Welsh speakers spotted the mistake.