The last major building work took place during the reign of King George V when, in 1913, Sir Aston Webb redesigned Blore's 1850 East Front to resemble in part Giacomo Leoni's Lyme Park in Cheshire. This new, refaced principal façade (of Portland stone) was designed to be the backdrop to the Victoria Memorial, a large memorial statue of Queen Victoria, placed outside the main gates. George V, who had succeeded Edward VII in 1910, had a more serious personality than his father; greater emphasis was now placed on official entertaining and royal duties than on lavish parties. He arranged a series of command performances featuring jazz musicians such as the Original Dixieland Jazz Band (1919) – the first jazz performance for a head of state, Sidney Bechet, and Louis Armstrong (1932), which earned the palace a nomination in 2009 for a (Kind of) Blue Plaque by the Brecon Jazz Festival as one of the venues making the greatest contribution to jazz music in the United Kingdom. George V's wife Queen Mary was a connoisseur of the arts, and took a keen interest in the Royal Collection of furniture and art, both restoring and adding to it. Queen Mary also had many new fixtures and fittings installed, such as the pair of marble Empire-style chimneypieces by Benjamin Vulliamy, dating from 1810, which the Queen had installed in the ground floor Bow Room, the huge low room at the centre of the garden façade. Queen Mary was also responsible for the decoration of the Blue Drawing Room. This room, 69 feet (21 metres) long, previously known as the South Drawing Room, has a ceiling designed specially by Nash, coffered with huge gilt console brackets.

Under whose reign did the last major building works take place?