Was it uncommon to see an Englishman with a cane or walking stick during WW1? Specifically, in Europe

Okay…a few definitions to be clarified here, note that I’m just talking about the British Army during WW1 (and the time just before and after): the swagger stick was what other ranks (Private to Colour Sergeant) carried while in ‘walking out dress’ (what you wore when you were off-duty), basically the same service dress uniform that was worn in the field, but minus the webbing and rifle (and with a khaki belt worn instead). Swagger sticks were usually about a foot long, with a brass end, which often had the regimental badge on it. You were supposed to carry it under your arm when walking, and the idea behind it was that it gave the soldier a sense of pride in his appearance, and gave him something to do with his hands (ie, he wouldn’t look slovenly by putting his hands in his pockets or what not). Remember, Britain’s army pre-war and after the war was an entirely volunteer force-we have only had conscription in the UK, at least as regards the Army, on two separate occasions: 1916-1918, and 1939-1961-and soldiering wasn’t exactly viewed by many of the public as a desirable, worthy or respectable occupation (the old adage “only thieves and vagabonds join the Army!) springs to mind.

So that’s the swagger stick. Note that the swagger stick was an infantry thing: cavalry troopers (and other mounted corps, like the Royal Artillery for example) would carry a short horse whip instead. But the function was very much the same.

If you look at photographs of the period, or just google “world war one uniforms”, you can see tons of staged portrait photographs of ordinary soldiers carrying swagger sticks (or the cavalry equivalent).

Now, the swagger stick is not to be confused with the officer’s walking stick, which was (and is) something else entirely. Much longer, and often (but not always) made out of rattan, you can find all sorts of variants of the time. Basically, because a commissioned officer was supposed to be a gentleman, and a gentleman of the time carried a walking stick (the origin of which is that it’s supposed to be in place of the court sword a gentleman carried in court dress), it was basically carried on occasions when an officer wasn’t carrying, and was carried in place of-his sword while off-duty (which given that officers from 1915 onwards were ordered to send their swords back home, was often). This is a tradition that is still to some degree with us today in the British Army: officers of the Royal Irish Regiment still carry a blackthorn walking stick (based on the traditional shillelagh), and officers of the Royal Tank Regiment still carry an ashplant walking stick. Some other regiments (such as the Welsh Guards) have in recent years resurrected this tradition.

If we just consider civilians, there were certainly men who still used canes as a fashion accessory in the early 20th century but they were not as common as during the Victorian era. Filmed street scenes from 1908 to the 1920s of Brussels (1908, 1914 and 1929), Paris, Berlin and London (1914 and 1918) all show men with walking sticks but they weren't many.

Among those who used them were Oscar Wilde (died 1900) and George Bernard Shaw (died 1950). As they were manufactured in other European countries, it seems fair to assume that an Englishman would not have felt out-of-place using a cane in those countries. Note that much of Belgium (including Brussels) was occupied by the Germans from late 1914 so it seems unlikely that that there would have been many English civilians around, although it would have been plausible before the occupation.

Walking canes or sticks began to loose popularity as a fashion accessory, status symbol and / or practical aid (for those who did not have a leg injury that is) at the beginning of the 20th century. Umbrellas and other items became more common. There were a number of reasons for this:

Until the 1800s, specialist carvers, metal workers, and artisans produced canes and walking sticks by hand. However, the popularity of fashion and gadget canes fueled a market for their mass manufacture and subsequently helped lead to their demise. By the late nineteenth century, materials could be sourced globally and produced in volume for public demand. Canes became less artistic and reflective of current fashions, and the modern crook-handled wood cane became the standard walking stick. By the turn of the century, walking sticks had become either novelty items or orthopedic aids. A London newspaper reported in 1875 how the usefulness of canes for many individuals had declined: "he needs not a help-he has no one to hit, and there is no one who will hit him; he needs not a support-for if he is fatigued, is there not the ponderous bus, the dashing Hansom, or the stealthy subterranean?" (Thornberry 1875).

...the visibility of canes and walking sticks as fashionable or ceremonial items declined more rapidly during the interwar period. The emergence of the automobile and public transportation and the fashionable popularity of briefcases and attachés rendered the cane less useful as a physical aid or storage device. It lost its traditional association with gentility, power, and authority, instead becoming a symbol primarily associated with the elderly or infirm.

Much of the cited passage above can be found in articles elsewhere: for example, the role of industrialization, standardization and their popularity as fashion accessories and social status. Thus, by 1940, they had largely fallen out of use except as walking aids. The availability of canes / sticks for collections seems to support this:

The decorative sticks we see today in collections are mostly from the 19th century and up to about 1920.

(For use in the military, see the comments under your post. See also A History of Walking Sticks.)