LONDON - Net migration to Britain fell to its lowest level in nearly six years during the year to June, driven by a fall in the number of European Union citizens moving to the country for work ahead of Brexit, official data showed on Thursday.

The Office for National Statistics said 212,000 more people moved to Britain than left, the lowest total since the year to September 2013.

Immigration of EU citizens fell to 199,000 the lowest level since the year ending March 2013, the ONS said, extending a declining trend since the 2016 referendum, when Britons voted by 52% to 48% to leave the EU.

By contrast, 151,000 EU citizens left Britain in the year to June, the largest total since records started 10 years ago.

Immigration is a hot political topic ahead of the Dec. 12 national election.

Prime Minister Boris Johnson has pledged to limit the number of people coming to Britain by implementing an Australian-style points system, while the opposition Labour Party said migration policy should fit the needs of the economy.

"While there are still more EU citizens moving to the UK than leaving, EU net migration has fallen since 2016, driven by fewer EU arrivals for work," the ONS said in a statement.

"In contrast, non-EU net migration has gradually increased for the past six years, largely as more non-EU citizens came to study."

Johnson has said Britain will leave the EU by the end of January if his ruling Conservatives win a parliamentary majority in a Dec. 12 election.

(Reporting by Andy Bruce Editing by Andrew MacAskill and Gareth Jones) ((andy.bruce@thomsonreuters.com; +442075423484; Reuters Messaging: andy.bruce.thomsonreuters.com@reuters.net))