According to details obtained by The Mail on Sunday, under the Freedom of Information Act, hundreds more illegal immigrants have been employed at 34 local authorities and 54 NHS trusts across the UK.
The news follows only months after attourney general Baroness Scotland was fined £5,000 for employing a house keeper who was not legally entitled to work in the UK.
But a Home Office spokesman told HR magazine: "The 12 illegal workers identified since 2006 were all sub-contractors, none of them were directly employed by the Home Office.
"It was our checks and the strict regime we operate on illegal working in the UK that brought these cases to light. We are doing more than ever before to crack down on illegal working, with raids taking place up and down the country every week, and thousands of rule breakers deported."
Eight of the 12 illegal immigrants employed by the Home Office have already been deported.
