Looking through the gatehouse of the Horse Guards building onto Whitehall from the courtyard. The gate is being closed behind the mounted guard on the pavement outside Link .
1888 puts it in the William Ewart Gladstone era; but is it he? If not, who then? There are apocryphal stories of notable Conservatives confusing the NLC for a public convenience when on their way to the House. Perhaps this is one of 'them' leaving.