There are around 1.24 million Brits living in Europe according to the latest 2015 UN global migration database figures in agreement with Fullfact, the UK's independent fact checking charity. (who probably got their figures from the UN report) Previous figures from the Institute for Public Policy Research (IPPR) in 2006, put it around 2.1 million.
Evidently, the figures are not completely accurate as requirements for registration vary across nation states, some people live part time in one country and part time back in the UK and some do not register with their local authorities.
Of the 1.24 million Brits in Europe, British in Europe estimate that around 200 - 250,000 are retired. So no more than 20%. The rest being of working age. There is a common misconception that the majority of Brits in Europe are retired. That's simply not the case.
The Department for Work and Pensions (DWP) pays out 490,869 British pensions a year according to the latest Sept 2016 from Stat-Xplore operated by the DWP. It's important to remember that a considerable number of these pensions will be received by non-British EU nationals who have gained a British pension by working in the UK and since left for retirement.
Therefore that 490,869 figure is significantly reduced.
According to Eurostat data from 2011, 79% of British pensions sent to Ireland are given to Irish citizens whereas 89% of British pensions sent to Spain are given to British citizens. Evidently the numbers of Brits at pension age in different countries varies considerably.
Fullfact, the UK's independent fact checking charity, in their 'Brits Abroad' report estimated that 5.5 million British people live permanently abroad – almost one in 10 of the UK population.
They estimate that 1.24 million Brits live in the EU which is broken down as follows:
Spain had the most British citizens living in Europe at 310,000
The Republic of Ireland at 250,000
France at 190,000
Germany is around 106,000
Italy at 26,000
As we've said figures vary somewhat between different data collecting and monitoring organisations but the proportion of Brits in different countries in the EU remain roughly the same.
INSEE, the national statistics organisation, issued 2016 figures in June 2020 which state the figures in France as 148,300 of whom 53,000 are retired. A further 86,000 second homes are owned by British nationals.