This morning Queen Elizabeth II of Britain attended a Cabinet meeting in 10 Downing Street. Unlike other European monarchs the Queen of Britain does not have regular meetings with the entire cabinet and this was the first time in her sixty years on the throne that she attended Cabinet. She sat next to Prime Minister David Cameron, but only participated as an observer and not for the entire meeting.
This does not herald a new practice, but was an exception to mark Queen Elizabeth’s diamond jubilee. It has been widely reported that she thus became the first monarch to attend Cabinet since Queen Victoria, but I cannot recall ever having heard or read of Queen Victoria attending Cabinet meetings. The historian Jane Ridley says something similar to the BBC, suggesting that it might have been George III, who "went only very occasionally". David Cameron himself said during today’s Cabinet that they had concluded that the previous occasion was probably George III in 1781. The last British monarch to take an active part in Cabinet meetings was Queen Anne.
There are currently 22 members of the British Cabinet, with ten more ministers able to attend. Of these 32 ministers only three were born when Elizabeth II succeeded to the throne on 6 February 1952.