It is a criminal offence for your employer to employ someone who doesn’t have the right to work in the UK and there are stiff fines and penalties for employers found to be employing illegal workers.
Employers are under a legal obligation to ask for proof of anyone’s right to work in the UK before employing them (and only certain documents can be accepted). Where a worker has limited right to remain, employers must repeat the check when their leave is due to expire. International students with a limited right to remain must show that they are following a course of study and provide evidence of term dates.
Employers can choose between a manual check of original documents and an online right to work check using the Home Office Checking Service.
Asking all job applicants to provide proof of their right to work in the UK is not race discrimination. Selecting only some individuals and not others – based on stereotypical assumptions about, say, appearance, accent, language or name – is likely to be race discrimination.
Your employer should be following a statutory Code of Practice (updated in 2014) Avoiding discrimination while preventing illegal working (PDF, 62 KB).