Some fascinating stuff here. "An American tourist's 100-year-old footage of the streets of London that shows residents of the capital going about their business as the First World War draws to a close has been found in an archive. Among the sights, many of which were captured as a moving image for the very first time, are famous buildings such as the Houses of Parliament, Windsor Castle and Tower Bridge. The video, which dates from 1918, was taken just months before the end of World War One by American traveller Elias Burton Holmes. In the archive footage, Eton schoolboys are seen larking in top hats and Downing Street is shown completely open in the days before armed police and large black gates were brought in to protect the Prime Minister. Meanwhile men wear bowler hats and horse-drawn carriages trundle gently down streets unencumbered by traffic." First World War London is revealed in archive footage | Daily Mail Online
Surprised to The Household Cavalry in full ceremonial uniform at 49 seconds. I was under the impression that was all put away until after the hostilities. I'm fairly sure The Foot Guards wore Service Dress whilst on Public Duties during the war. edit: found a longer version.