LONDON One of the toughest choices facing Britain as it prepares to leave the European Union is what system it will use to govern immigration from the bloc.
Prime Minister Theresa May has said she will heed the message from voters about the need to control the number of workers coming from the EU, but she also wants to secure the best deal possible for Britain's economy.
Under the EU's treaties, full access to the bloc's single market of more than 500 million consumers depends on countries opening their borders to workers from EU countries.
Below is a summary of options for Britain's immigration system once it leaves the EU.
Workers hoping to move to a country are typically awarded points based on criteria such as education, age, income and skills. Australia's system has been supported by prominent Brexit supporters and New Zealand and Canada use points too. But May has said loopholes in points-based systems means the government would not have enough control over migration. Britain uses a points-based system for migrants from outside the EU for which there is no overall cap. In 2015, net migration to Britain from outside the EU was slightly higher than from inside the bloc. Many employers have complained the points system is cumbersome and expensive. If Britain uses something similar for EU migrants, it would probably be seen as a breach of the bloc's rules on free movement, jeopardizing British access to the single market.
British Finance Minister Philip Hammond said on Thursday he wanted to ensure that the country's financial services industry was able to continue recruiting large numbers of workers from the bloc, a major concern of international banks.
"I would expect that using the control that we will have over the movement of people, we would use it in a sensible way that would certainly facilitate the movement of highly skilled people between financial institutions and businesses in order to support investment in the UK economy," Hammond said.
His comments suggested the government may seek to offer more access to migrant workers with skills that are in high demand for specific sectors of the economy.
THE "GREEN CARD" OPTION
Under the U.S. immigration system, lawful permanent residents are granted so-called green cards which gives them permission to live and work in the United States permanently with the backing of a U.S. employer.
Inflows of foreign population into the United States granted permanent residence have been stable over the past decade, at around 1 million a year, the OECD says. However, the process of securing a green card can be complicated and drawn out.
A similar scheme used by Britain would probably cause it to lose some of its access to the single market.
Britain is unlikely to want to adopt the U.S. system of using a green card lottery to allow people into the country which does not target migrants based on skills.
FOCUS ON WORK PERMITS
Britain could waive controls on individuals from the EU such as students and pensioners who are considered to be self-sufficient but rely on a points-based system to cap the number of work permits for EU and non-EU nationals. MigrationWatch UK, an advocacy group, has said this could cut EU net migration by 100,000 a year from its 2015 level of about 180,000. However, some have challenged this figure for assuming the UK would exclude low-skilled workers from the permit system. Once again, restrictions on EU workers would probably be deemed a violation of the EU's freedom of movement principle, effectively restricting access to the single market.
UNSUCCESSFUL JOBSEEKERS FORCED TO LEAVE
Britain could get tougher about forcing EU job seekers to leave if they fail to get a job after a certain period of time. EU legislation allows countries to deport EU citizens if they remain jobless after six months but it is unclear how often the rule is enforced. Stronger rules could require job seekers to register with the government but it is not clear how effective it would be and whether any tougher approach by Britain would break the EU's principle of free movement.
PROLONG AN "EMERGENCY" BRAKE ON IMMIGRATION
Britain could choose to keep the EU's freedom of movement principle even after leaving the bloc but try to negotiate the option to pull an emergency brake on migration. The rules of the European Economic Area, of which Britain is a part, allow for a temporary halt to immigration under exceptional circumstances.
The Institute for Public Policy Research, a think tank, says Britain might be able to halt migration for a longer period of several years without renouncing its access to the single market, if it could show EU migration was hurting UK wages.
Even if the EU were to agree to this, the IPPR said the UK would likely still have to contribute to the Union's budget, which would be opposed by many supporters of Brexit.
(Editing by William Schomberg and Richard Balmforth)