The civil offence

• The nature of the checks carried out by the employer
• The number of offences previously committed by the employer
• If the employer reported suspected illegal workers to the BIA
• Whether the employer co-operates with the BIA in any investigation

An employer may have a statutory defence to the civil offence under section 15 if they obtain and check certain original documents before employing the prospective employee.

The employer must take reasonable steps to check the validity of the documents provided by the prospective employee. This will require the employee to undertake basic visual checks to ensure that the documents relate to the potential employee by comparing any photographs in the documents and dates of birth against the appearance and apparent age of the potential employee. The employer must also check that any government endorsements entitle the potential employee to undertake the type of work on offer and that no expiry dates have passed. The employer is further required to take copies of the documentation provided by the individual and retain these copies for at least two years after the employment terminates.

Employers will have the right to object to the BIA, or appeal to the courts if they believe that the service of a civil penalty is unjust.

The criminal offence

Under section 21 of the 2006 Act, an employer who knowingly hires an illegal worker will commit a criminal offence and be liable to a custodial sentence of up to two years and/or an unlimited fine. The statutory defence available will not apply where an employer knows that they are employing an illegal migrant worker.

Those employed prior to 29 February 2008

Whilst the new offences outlined above replace a previous offence under the Asylum and Immigration Act 1996 ("the 1996 Act"), this offence still applies in relation to individuals that were employed prior to 29 February 2008.

Under section 8 of the 1996 Act, it is a criminal offence to employ an individual who was subject to immigration control who has no permission to work in the UK, or his employment is in breach of their conditions of stay in the UK. Any employer in breach of section 8 is liable, on summary conviction, to a fine not exceeding £5,000 per illegal worker. The Asylum and Immigration (Treatment of Claimants, etc.) Act 2004 ("the 2004 Act") made this summary offence triable either way and, therefore, any employer prosecuted in respect of this offence could receive an unlimited fine in the Crown Court.

However, section 8 of the 1996 Act allows an employer to establish a statutory defence against conviction if, before the employment began, the employer had carried out the required checks of the potential employee's original documentation and he is satisfied the employees have the required immigration permission. Copies of the documentation must be kept for the employer's records. An employer could not rely on the statutory defence if it had made the relevant checks but knew that the individual was not entitled to work in the UK.

The Immigration (Restriction on Employment) Order 2004 ("the 2004 Order") tightened the list and the combinations of documents that employers must check and attempted to eliminate documents that have proved venerable to forgery.