By Kylie MacLellan
LONDON (Reuters) - Net migration to Britain fell slightly in the year to March but remained close to record levels, official data showed on Thursday, the first to be released since the June 23 vote to leave the European Union.
Prime Minister Theresa May has said the result of the EU referendum, in which immigration was a key part of the debate, was a message from British voters that they wanted to see fewer people coming into the country.
The Office for National Statistics (ONS) said net migration to Britain was 327,000 in the year to March 2016, a fall of 9,000 on the previous year. The most common reason given for coming to Britain was work, it said.
In the year to June 2015 the number hit a record high of 336,000, more than three times the "tens of thousands" level promised by May's predecessor David Cameron.
May, who took office last month, has repeated the pledge to get yearly net migration down to the "sustainable" level of less than 100,000, but has not yet set out any details of what restrictions might be put in place.
"The opportunity that Brexit presents is to impose controls on people coming from the EU to work here. It is early days in the negotiation but certainly that does present an opportunity," immigration minister Robert Goodwill told Sky News.
"We need to identify where there are skills shortages and ensure that if we do have people coming in, they fill those shortages."
The Telegraph newspaper reported on Thursday that under plans being considered by ministers, low-skilled migrants from the EU could have to apply for permits to work in Britain after it leaves the bloc.
David Metcalf, head of the Migration Advisory Committee, the body which advises the government on immigration issues, told the paper that both the number of migrants and the time they spend in Britain could be controlled using permits.
Net migration from the EU was estimated to be 180,000 in the year to March, down 4,000 from the previous year, the ONS said.
It said net migration from Bulgaria and Romania, whose citizens faced restrictions on working in Britain until January 2014, had reached a record level of 61,000, up from 51,000 a year earlier.
Migration played a key role in the debate ahead of the EU referendum, with 'Out' campaigners saying Britain would be better able to control migration from outside the bloc.
May has said she wants EU nationals already in Britain to be able to stay but that this will depend on the status member states give British nationals living elsewhere in the EU.
"The government must also clarify how new EU hires will be treated, as many businesses also say they are uncertain about whether the people they wish to recruit will be able to continue working with them in future," British Chambers of Commerce Acting Director General Adam Marshall said in a statement.
(Editing by Stephen Addison)