Britain gave 125,605 citizenships during the 12-month period, including 17,900 to migrants from India, 10,300 to people from Pakistan and 6,400 to Nigerians.
Eight per cent of British citizenships granted went to people from other EU nations while the rest came from outside the EU.
Almost two thirds of the 35,300 people from India who acquired EU citizenship in 2014 did so in Britain, according to the research.
Since 2009, early four million people have been given citizenship by other EU nations and 1.1 million by the UK, but the number dropped from 203,000 in 2009 to 125,000 in 2014.
The Eurostat figures follow a report from the think tank Migration Watch published yesterday forecasting an extra 100,000 migrants a year will come to Britain if Turkey joins the EU.
A spokesman for the Britain Stronger In Europe campaign said: “The overwhelming majority of independent experts agree that leaving the EU would damage the economy – pushing up prices, risking jobs and reducing the amount of money available for public services like the NHS.