Attached is a photo taken at Truro Station recently. In the left foreground is a ground disc signal which once upon a time controlled entry to the sidings on the south side of the line east of the station. The sidings were taken out of use many years ago and dwellings were built on the site. The point survived for many years, at first complete, and then partly complete. Even the last remains of the point were removed a couple of years ago. Yet the ground disc survived. I wonder if it now has any function? The cross-over has its own ground disc signal which can be seen just before the cross-over.
Regards Mike See answer from Roy Hart below
The disc has a very important function: it signals backing movements over the level crossing towards the crossover.
Roy Hart Many thanks Roy