http://www.parliament.uk/faq/gunpowder_plot.cfm
"Are the Houses of Parliament still searched before State Opening?
The Houses of Parliament are still searched by the Yeomen of the Guard just before the State Opening (usually held in November since 1928) to ensure no latter-day Fawkes is concealed in the cellars, though this is retained as a picturesque custom rather than a serious anti-terrorist precaution (for which, of course, there are proper means). "
