The Brampton for was a little different in terms of how the fore-and-aft movement was controlled.
On a Triumph, the part connecting the stirrup on the head-stem to the top of the forks was the spring.
On the Bramptons there are studs, on which a sliding block is positioned between two springs (one central stud on the veterans, two on the 20s forks), so you effectively have sprung top links.
In theory, nothing too drastic would happen if a spring failed.
