The UK government should drop its controversial "tens of thousands" net migration target and adopt a US-style quota system, a former adviser to the Home Office said on Friday (27 January).
Professor Jonathan Wadsworth, who sat on the Migration Advisory Committee (MAC) for nine years, said the move would be a "sensible" reform.
"We are the only country that has a net migration target, other people have quotas on the number of people coming through," he said.
"If you are thinking about designing immigration policy, [a quota system] would probably be the most sensible place to start, rather than having a target over which you have very little control."
He added: "The reality is that any target is reasonably crude and you're obviously balancing economic efficiency against the reality of public policy – there seems to be a demand to be seen to be controlling immigration."
The "tens of thousands" target was part of the Conservatives' 2010 and 2015 general election manifestos.
But the latest figures from the Office for National Statistics (ONS) showed that net migration hit more than 335,000 in the year to June 2016.
The immigration issue was a major debating point of the EU referendum, with Vote Leave campaigning to stop the free movement of people from the continent and endorsing an Australian-style visa system.
May is also expected to focus on migration rules as part of the UK's divorce talks with the EU. European Council chief Donald Tusk has ruled out so called "single-market al a carte" for the UK – extensive access to the bloc and immigration curbs.
Wadsworth said the way migration to the UK is measured should also be changed in a bid to improve the way policy decisions are informed.
The ONS currently uses the International Passenger survey to monitor flows of people in and out of Britain. "It would be probably easier to go towards... monitoring of both entry and exit checks on visas," the academic argued.
Wadsworth said those checks are "beginning to happen now", but warned it was harder to measure exits and the problem with the system is that EU citizens currently do not require visas to travel to the UK.
"The International Passenger Survey is a reliable way of measuring international migration to and from the UK," a spokesperson for the ONS said.
However, ONS is already working closely with other government departments to improve the range and accuracy of migration data available to us. We are making good progress in several areas and will continue to provide regular updates on future developments."
A Home Office source said the UK needs a "fair and controlled" immigration policy, which the government plans to deliver. But the source recognised there was "no quick fix" to the issue.