Horse Guards (15072321110). German postcard

A Tuck's Oilette first published in 1904 and painted by Harry Payne with the assistance of his brother Arthur. This must be one of hundreds if not thousands of postcards depicting the mounted Guard of one of the Household Cavalry Regiments at Horse Guards in Whitehall and in this case the Life Guards, but this is the only one I have seen in which the Guard has been armed with a rifle.