In the i newspaper (stripped down version of the Independent) today they gave about 148,800 British in France and 155,000 French in UK. Only half the UK citizens were working. 67 of the French were working or studying. 2 in 3 of the French worked in "higher level proffessions"
I think the 300K figure is also correct but includes people on extended visits or working for a few months.
This also applies to other countries such as Spain where many people work in Bars etc for a few months then come back to the UK so do not show up in residence surveys.
Figures are as valuable as knowing the definitions behind them
All in all the figures were higher than my gut feeling. I could not resist digging a bit further in Spain, that 1 Mio of the graph. I thought a big portion would be pensioners, which was not the case.
From the Guardian this expats overview:
Top 10 destinations for UK expats*
Australia 1,062,000 (251,000)
USA 829,000 (140,000)
Spain 808,000 (104,000)
Canada 608,000 (157,000)
Ireland 289,000 (126,000
France 253,000 (57,000)
New Zealand 248,000 (54,000)
South Africa 219,000 (38,000)
Germany 97,000 (39,000)
UAE 65,000 (680)
*Table shows numbers of expats in each country, and in brackets the number of pensioners
https://www.theguardian.com/money/2012/nov/26/where-do-uk-expats-live