Owners of small or mediumsized businesses may not think that immigration law affects their business - but the law says differently.

Last year the Home Office set up no fewer than 1,600 operations to tackle illegal working.

They uncovered 3,330 illegal workers and as a result a number of businesses in the West Midlands found themselves facing criminal liability for employing them.

And the crackdown is continuing with one major West Midland employer cooperating with the Home Office in a further operation to detain suspected illegal workers.

Claire Andrews, a solicitor with Putsmans in Birmingham, explains why the issue is becoming more important to regional businesses.

"The Asylum & Immigration Act 1996 introduced criminal liability for employers who employ persons whose immigration status prevents them from working in the UK," she said.

"Even though this legislation has been around for some time, many employers still do not have the requisite procedures in place to verify a new or prospective employees' immigration status.

"Currently, failure to comply with these obligations may render a manager personally liable to a £5,000 fine for every illegal worker they 'knowingly' employ, as well as exposing their business to damaging publicity."

The Government has recently unveiled its proposals to step up its enforcement against employers who break the law in this area.

Under the new Immigration, Asylum and Nationality Bill, on the spot civil penalty fines of £2,000 per illegal worker will be imposed on businesses.

Firms or individuals who "knowingly" employ an illegal worker also face a jail term of up to two years and unlimited fines. This is set to update the current legislation which set the maximum fine at £5,000.

Explaining the possible financial implications of not following the new procedures, Ms Andrews says: "The fines will be imposed on employers who are found to be employing illegal workers and who have not asked to see appropriate documents, copied them or taken steps to check they were authentic.

"Employers will also be required under the new legislation to check 'at prescribed intervals' that their migrant workers are entitled to be in the UK.

"Criminal liability is not confined to the corporate employer but also extends to any director, manager, company secretary or similar officer where the offence of employing an illegal worker has been committed with their consent, connivance or neglect.

"This means in practice that anyone with HR responsibility could also be prosecuted.

"There is currently a statutory defence against prosecution, however a business must be able to show that they have checked and copied original documents which appear to demonstrate that a new or prospective employee has permission to work in the UK.

"It is important for businesses to remember they can ask for this information at any stage of the recruitment process but information must be checked before the individual starts work if a business ultimately needs to rely on the statutory defence."