WW1 Ambulance Column London District tribute pin brooch

A rare original circa end of First World War period 'Ambulance Column tribute pin badge'; small unmarked silver example mounted on a gold coloured bar, the central cross set with red cut stones. Very good condition. Height 20mm. Width approx 40mm. The 'Ambulance Column attached to London District' was a World War 1 raised unit (1914 to 1919) formed for the transporting of sick and wounded soldiers by ambulances from 'London Train Stations' to various hospitals in and around London.