The Office for National Statistics data contradicts the widely held belief that most Britons in Europe are pensioners sunning themselves in southern France or Spain.
ONS figures show two-thirds of the 784,900 British citizens recorded as long-term residents in the EU, excluding the UK and Ireland, are aged between 15 and 64 and more of them live in Spain than any other country.
Estimates using data from the Labour Force Survey and the 2011 European censuses put the number of British people resident long-term in Spain at 293,500.
France is the next most popular country to live in, with 152,900, followed by Germany, with 96,500, and the Netherlands with 45,300.
The data has been published as part of the last of a series of ONS reports called Living Abroad: British residents living in the EU, designed to build a picture of those outside the UK who are affected by Brexit.
Ireland has been excluded from the report partly because British citizens in Ireland and Irish citizens in the UK will not be affected by changes to citizens’ rights after Brexit.
The report uses UN migrant data to show that, when it comes to emigration, the UK is the least Europhile nation in Europe. It came bottom when comparing the proportion of the population emigrating to another EU country, just behind Malta and Croatia.
Just 26% of migrants who were born in the UK and living abroad were living in the EU. In contrast, 44% of emigrants born in Germany moved to another EU state, while 49% of those born in France followed suit.
Of the EU countries, citizens of Luxembourg are most likely to move to another state in the bloc. That is likely to reflect its size and geographical location close to bigger cities such as Brussels, Paris and Frankfurt.
“Spain continues to be the most desirable location for the three quarters of a million Brits living in the EU. However, the EU as a whole is not the most popular destination for British expats, with more than half preferring to live in English-speaking countries,” said Jay Lindop, the deputy director of migration statistics at the ONS.
The most common destination for the 4.9m UK-born emigrants were English-speaking countries. Australia and New Zealand are home to 33% of all emigrants. The US and Canada are the next most popular, accounting for 28% of UK emigrants between them.
For retirement, Spain is still the No 1 destination for Brits, followed by Portugal and Bulgaria, which rocketed up the league of nations attractive to British and Irish people just before the financial crash because of cheap property in Black Sea resorts.
Among the countries with most British children under 15 are Luxembourg, Slovakia, France and Belgium.
The highest proportion of British citizens of working age are in Finland and the Czech Republic, at 88% and 87%. By contrast, 53% of those in Spain are aged 65 or over.
Lisa O’Carroll, Brexit correspondent