There was a net flow of 243,000 long-term migrants to the UK in the year ending March - up from 175,000 in the previous year.
The Office for National Statistics said the overall net migration - the difference between migrants leaving and arriving in the UK - had seen a "statistically significant increase".
Two-thirds of all immigrants to the UK within this period came from within the European Union.
Prime Minister David Cameron and Home Secretary Theresa May previously pledged to cut net migration to below 100,000 by the 2015 General Election.
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