Summary: As per this month's data from statCounter, France crosses a milestone; "Linux" is at over 40% and Windows is on fewer than 1 in 3 clients observed by sites statCounter tracks (about 3 million sites)
"In the United Kingdom, the Foreign Enlistment Act 1819 and the Foreign Enlistment Act 1870 make it unlawful for British subjects to join the armed forces of any state warring with another state at peace with Britain."