1921 Census of England and Wales, General Report with Appendices, Table 64 : " Birthplaces of Persons of Foreign Nationality, 1901-1921".

Where Born. Number. Per Cent. of Total Foreigners.
1901. 1911. 1921. 1901. 1911. 1921.
Russia (including Finland) 61,789 62,862 49,360 24.9 22.0 21.5
Poland* 21,055 32,679 35,536 8.5 11.5 15.5
France 20,467 28,827 23,659 8.3 10.1 10.4
United States 16,668 13,637 19,171 6.7 4.8 8.3
Italy 20,332 20,389 19,098 8.2 7.2 8.3
Germany 49,133 53,324 12,358 19.8 18.7 5.4
Belgium 4,314 4,657 9,681 1.7 1.6 4.2
Switzerland 8,357 10,267 8,965 3.4 3.6 3.9
Netherlands 6,851 7,643 7,426 2.8 2.7 3.2
Denmark 3,363 4,557 4,700 1.4 1.6 2.0
Sweden 5,515 5,953 4,425 2.2 2.1 1.9
Norway 6,207 5,697 3,534 2.5 2.0 1.5
Spain 2,781 3,635 3,292 1.1 1.3 1.4
Greece 1,045 1,278 2,432 0.4 0.4 1.1
China 387 1,319 2,419 0.2 0.5 1.1
Turkey (including Armenia) 1,589 2,651 1,016 0.6 0.9 0.4
Portugal 413 740 968 0.2 0.3 0.4
Europe (other Countries) 14,090 18,494 10,677 5.7 6.4 4.6
Africa 462 1,035 655 0.2 0.4 0.3
America (except United States) 1,643 3,223 3,559 0.7 1.1 1.5
Asia (except China and Armenia) 858 1,741 4,394 0.3 0.6 1.9
At Sea† 439{ 230 1,868† }0.2{ 0.1 0.8†
Not stated 222 941 0.1 0.4
             
TOTAL 247,758 285,060 230,134 100.0 100.0 100.0

* The figures for 1901 and 1911 refer to the area then described as Russian Poland.

† Of the 1,868 persons born at sea not specifically returned as British subjects, 113 described themselves as of foreign nationality while in 1,755 cases the nationality was omitted. The rule, treating foreign-born persons of unstated nationality as equivalent to aliens, cannot fairly be applied to persons born at sea and, in respect of this class, the 1921 figures shewn in the table undoubtedly overstate the facts by a large amount, the total number of aliens being probably but little in excess of the 113 specifically described as such.