The Immigration Minister Damien Green has announced that employment restrictions on Bulgarian and Romanian nationals will be extended until 2013. This is in response to a Migration Advisory Committee (MAC) report that says removing the restriction will lead to more migration here from these countries and displace resident workers in low skilled jobs. It is also said that this will have a "negative impact" on wages.

Economist Diane Coyle has noted that migrant workers in the UK tend to be either very highly skilled or low skilled, which suggests that they are filling gaps in specific areas of the labour market, not taking jobs from the native or resident population. And Bryan Caplan explains that by doing low-skilled work migrants enable more productivity in the native labour force.

Caplan argues that the native workers don't have to spend time doing daily, menial chores and are free to focus on improving their skills, and working harder. And this increases wages.

The MAC themselves say,

Many empirical studies find no statistically significant impact of migration on the employment levels of non-migrant workers.

Whilst recognising that there is no long-term negative effect of migration on native work, that it increases productivity, increases the employment rate, and increases economic growth, the MAC report does say:

during economic downturns, new immigrants have a small negative short-run impact on the employment rate of natives.

But there are no short-term solutions. This is not a short-term policy. Unemployment won't suddenly fall because we stop productive labour coming into the country. As the MAC admits itself, the "impacts would be small in comparison to the ongoing adverse impacts of the recent recession."

They even say that the extent to which keeping the controls will help the labour market is "subject to considerable uncertainty."

The explanation for why we should lift this restriction is the division of labour. Let's take the example of a restaurant.

If the chefs had to order supplies, lay tables, serve plates, look after wine, wash up AND do the cooking then the food would be bad and the chefs exhausted. By employing waiters and cleaners, and using food suppliers, the restaurant becomes more productive - it can do more things in the same amount of time, and the chefs are able to spend more of their time cooking and improving their skills. And at the end of the day there is still enough time for them all to go home and relax. Or revise for the exams that will get them their next better-paid job.

It's the same with an immigrant work force. As Bryan Caplan says, "immigration encourages natives to specialize in jobs where they are especially productive - and sub-contract their other jobs to the new arrivals."

Henry Oliver writes the blog for Mulberry Finch.