I was curious, having heard recordings of Canaro playing foxtrot. & of course we know from the old-timers that it used to be a popular dance in Buenos Aires alongside tango. YouTube found me this:
Fascinating! First off, I checked the British Pathe site, and the film is early 1920s, so it is silent. The soundtrack has been added, but it seems to fit the dance well enough to give an idea of the musicality.
So it's an upright and close-embrace dance! Quite unlike the ballroom version. & doesn't it look as if it could be an improvised dance? It's a walking dance with a traspie to the front and side, the sort of thing you could improvise as the music played, especially since the embrace is close: as in tango, the leader's torso would signal movements. Of course, the partner would be listening to the music too, and would know what to expect. It doesn't look like it needs to be a choreographed dance.
Wikipedia is the next port of call. Why is it called Fox Trot? Because the basic walk is danced with the feet along a straight line: the prints of a fox's paws in the snow are in a straight line. (The prints of a dog show two lines.) Fascinating! Especially since that's the effect of 'collecting'. I find 'collecting' hard to remember and practice, but think of it as stepping in exactly the place your partner's foot has just left and it makes sense, to me anyway. It's a very neat, tidy walk, stepping right under your partner. Watch any video of Osvaldo and Coca...
The Foxtrot was picked up around 1912 by Vernon Castle, from an 'exclusive coloured club' where it had been danced for some years. Vernon and his wife Irene were prominent US dance teachers and enthusiasts for Afro-American music. It was to become the most popular of social dances; most dance records up until the 1950s were foxtrot.
Two curious facts: when the Castles first introduced it they called it the 'Bunny hug' -- and then decided better. & when Decca released Rock around the Clock they didn't know what to call this kind of music, so they called it a Foxtrot. Rock around the Clock was the best-selling foxtrot of all time.
Couldn't the foxtrot make a come-back? Not the (rather absurd) choreographed ballroom version, but the neat, elegant version of this film, which I'd assume is much closer to the original? Alongside tango, vals, milonga? It seems to belong to that family of dances, even if the music is different.