Legal experts are warning bosses of small and medium-sized businesses to make sure they are taking adequate precautions to ensure that the staff they employ have the right to work in the UK.
The caution comes following news that the EU is planning a crackdown on black market workers and may impose tougher penalties on those that employ them.
There are an estimated three to eight million illegal immigrants in the EU and the figure is thought to be allowed to increase due to the accessibility of illegal employment.
Ansar Ali of law firm DWF says: "As well as the risk of a fine or even a jail sentence, employers may be liable for any unpaid taxes and social security payments, as well as the cost of repatriating the worker."
He adds: "Given the raft of changes in this area of the law, employers should be mindful of their obligations since the penalties for non-compliance could be severe."