The Home Office has published new proposals for rules relating to the employment of overseas and foreign workers. Under the rules firms will have to prove that they could not employ someone from the UK before offering jobs overseas.

The proposals relate to the Home Office's Points Based System for employing workers, and form two schemes - Tier 2 and Tier 5, both of which replace the old work permit system. The new system is based on points, meaning that potential workers will have to prove that they have gained enough to qualify to apply for a visa.

Points are awarded for a number of reasons, including what work they are currently engaged in, whether they are able to speak English, earn above a certain amount, or have a high level of qualifications. Most importantly however is the fact that British firms will have to prove that they cannot fill any advertised roles with a resident worker, and the job must have been advertised within the UK before opening up the recruitment process overseas - a situation that could affect firms currently employing foreign IT workers to fill UK-based positions.

Home Office figures suggest that had these rules been in place last year, around 20,000 less overseas workers would have been allowed into the UK. Border and Immigration Minister Liam Byrne said, "Our new points system means that British jobseekers get the first crack of the whip and that only the skilled migrants we actually need will be able to come.

"By moving points up or down, we can make sure the numbers we allow in to the UK are in line with the needs of business and the country as a whole.

Business that ignore the new rules faced increased punishments, the Home Office added. Under the new illegal working regime 137 businesses have already been issued with Notices of Potential Liability worth almost half a million pounds.