“A member of Parliament was ceremonially held hostage in Buckingham Palace while the queen visits Westminster, just in case the lawmakers decided not to return her. This is rooted in the 1600s, when the relationship between Parliament and the monarchy was particularly fraught under Charles I.”
| A Guide to the Queen’s Speech: Crown Jewels, Black Rod and a Mace - The New York Times https://www.nytimes.com/2019/10/14/world/europe/britain-parliament-queen-speech.html?te=1&nl=morning-briefing&emc=edit_NN_p_20191014§ion=whatElse?campaign_id=9&instance_id=13056&segment_id=17862&user_id=f595535cce9222e1770107fb8e8f0cc1®i_id=86923769ion=whatElse