Iain Duncan Smith is a former Secretary of State for Work and Pensions, founded the Centre for Social Justice, and is MP for Chingford and Woodford Green.

The central objective of a post-Brexit migration policy should be to regain control over the movement of people into the UK. Using a combination of work permits and a cap, we would be able to control access to work and rights to settlement. Free movement for EU citizens for other purposes should be preserved.

Too many engaged in the debate on migration seek to vilify the idea of controlling migration as anti-migrant, but it is not. It is simply a recognition that the pace and scale of migration in the past few years has been unprecedented, which has caused difficulties in a variety of communities.

Despite some of the commentary, and the casual references to historic waves of migration coming to the UK, the reality is a little different. Over the centuries, migration was on a very small scale compared to the size of the population. For example, in the 17th Century, some 50,000 French Huguenots arrived in Britain over a 40-50 year period, approximately 10,000 a year. Jewish refugees fleeing Russia, Eastern Europe and Germany arrived in Britain during the 19th and 20th centuries – around 200,000 over a 50-year period. In the 13 years between 1997 and 2010, net foreign migration totalled 3.6 million.

Even in the decades between the Second World War and the late 1990s, whilst immigration grew steadily it did so at a relatively modest rate before declining in the late 1960s and becoming fairly stable between 1971 and 1981. With net migration currently standing at a third of a million, the increased level of migration since the late 1990s has dwarfed the scale of anything that came before.

That is why the objective of any new migration policy must be to get this into balance, so that the UK can continue to be able to attract those needed to work, but do so at a sustainable rate that can be absorbed whilst adding value to the economy.

There are some key objectives when looking to take back control of migration from the EU. First, those EU nationals wishing to come to the UK for work should be brought within the present UK work permit system. The level of the cap on work permits should be a matter for a new government to decide; meanwhile, Intra Company Transfers (ICTs) would be unrestricted unless they became open to abuse.

Second, the Government should ensure that the eventual system is as flexible as possible for those areas of high added value but low-volume employees. Examples of those would be academics, scientists and people in financial services. In these categories it should be possible to arrange processes by which a very light-touch system operated with much fewer restrictions. (It is worth recording that the UK is different from some other nations, in that much of its applied research work, relevant to industrial use, is carried out by universities and thus those engaged in this high value work would need to be treated in the same flexible manner.)

Furthermore, free movement for EU tourists, students and the self-sufficient (such as pensioners) could continue in both directions, as they are not competing for work and have little impact on the permanent population. There should be no restrictions on genuine marriage (although robust checks should be in place), and last but not least, people should be expected to have secure employment to go to before entering the country.

Alongside this there is also the issue of benefit access to be considered. Although not all the figures are in the public domain, the last available figures finally published by the Government show that EU citizens in the UK received over £4 billion in benefits.

Whether you believe this is a pull factor or not, it makes sense to bring this cost under control. To do so, people allowed in to work should have to have a record of contributions over a period of time before being able to claim support from the state. This will also help stop the abuse of migrant workers from unscrupulous employers who pay very low wages in the anticipation that these will be topped up by tax credits and family benefits.

The new system will also need to be flexible and should allow the Government from time to time to exempt some occupations from any restrictions whilst tightening up on other occupations, thus allowing them to cater for both changing circumstances and the economic cycle. The Migration Advisory Committee’s Shortage Occupation List could be used for this purpose. For example, high added value migrants who are low in number, for example scientists and software engineers, might be exempted but a range of lower-skilled work would be restricted by both the cap and the permit system.

Where the issue of a permit is being considered, DWP’s regional Job Centres should be involved to check whether there is actually a shortage of UK labour in that category and location before issuing permits to business. It should be possible to leverage information gathered from the implementation of Universal Job Match and the new Work Coach Programme, plus in-work conditionality, to provide new and much better data-driven insights into the potential supply of labour already available.

Some enhancement of the National Insurance number system could be required to distinguish between those granted to immigrants for work and for other purposes. This would possibly allow a time limit to be set on their validity, meaning that they would lapse on expiry of the work permit and guard against ‘disappearance’.

There has been much ill-informed commentary about the problems that would beset those farms and other businesses which at present rely on seasonal workers. The reality is quite different. The Government would be able to introduce a Seasonal Agricultural Workers Scheme; after all, such a scheme ran successfully for many years and was only brought to an end when the UK’s borders were opened to unskilled workers from Eastern Europe.

Interestingly, New Zealand’s seasonal workers scheme offers us a guide to how this could operate now. It provides places to work during the agricultural season. Employers must register as a Recognised Seasonal Employer before applying to recruit workers. They must pay the market rate for work being carried out, a measure which aims to avoid the undercutting of local workers by immigrant labour. Furthermore, employers must pay half the worker’s return air fare and bear the cost of repatriating workers if they become illegal.

In conclusion, it is important to remember that one of the reasons people voted to take back control in the referendum, was to ensure we tightened up on the levels of migration. If we are to restore the confidence of the public that their voice was heard, it is vital that any migration policy does just that. I believe these suggestions should help make the new migration policy workable.