LONDON (AFP) - Britain’s Queen Elizabeth II attended her first-ever cabinet meeting on Tuesday to mark her diamond jubilee, the only monarch to do so since 1781. Wearing a royal blue coat and dress, the 86-year-old sovereign was greeted by Prime Minister David Cameron outside the door of his official residence, 10 Downing Street. The queen received a diamond jubilee gift of 60 placemats from the cabinet to mark her 60 years on the throne and spent half an hour at the meeting as an observer, officials said. Cameron said it was the first time a monarch had visited a cabinet meeting since king George III in 1781. The PM offered Queen a “very warm welcome” after she took her seat in the middle of the cabinet table, with Cameron to her right.