The Geat Western Railway (GWR) linked London with the Midlands, the South-West and West of England and most of Wales. It was founded in 1833 and operated from 1838 until 1948.
The GWR was the only company to keep its identity through the Railways Act 1921, which amalgamated it with the remaining independent railways within its territory, and it was finally merged at the end of 1947 when it was nationalised and became the Western Region of British Railways.
The company is known to have used two types of handstamped overprint on the 1d lilac Inland Revenue stamp. It seems unlikely that these overprints served as a security device, as the stamps shown here have already been perfinned and I have yet to see any examples without a perfin. The significance of the dates in the overprint is not known. It has been reported that the stamps were used with Debenture Stock Interest Warrants issued by the GWR.