The UK Border Agency publishes guidance for employers on preventing illegal working. 

An employer is acting unlawfully if they employ a person who does not have the right to work in the UK and can be fined up to £10,000 per illegal migrant worker. 

Where employers are found to be breaking the law, the UK Border Agency takes enforcement action. 

The latest guidance and news updates to help you prevent illegal working can be found on the Gov.uk website 

The Full Guidance for Employers on Preventing Illegal Working includes details of the document checks that employers are advised to undertake and images of the documents and stamps/endorsements that may be presented by migrant workers as evidence of their right to work in the UK.