Battle of Britain, wrote in his book, Dowding and the Battle of Britain, that even when faced with threats of retirement and constant rebuttal, Dowding continued to give his all to those under him and the RAF service. Dowding noted in a letter Air Ministry in early March 1940, that: "Apart from the question of discourtesy, which I do not wish to stress, I must point out the lack of consideration involved in delaying a proposal to this nature until ten days before the date of retirement. I have had four retiring dates given to me and now you are proposing a fifth. Before the War, as I told S of S, I should have been glad to retire: now I am anxious to stay, because I feel that there is no one else who will fight as I do when proposals are made which would reduce the Defence Forces of the Country below extreme danger point." Bentley Priory continued to act as the Headquarters of Fighter Command throughout the Second World War. It assumed additional importance as the Air planning headquarters for D-Day, as the planning for the full operation was conducted at near Portsmouth, with Montgomery, Eisenhower and Churchill attending a nearby church the evening before the assault. Much of the detailed air planning work was carried out at Kestrel Grove just a few hundred yards away (this building still stands and is now a retirement home). On D-Day, the landings were monitored by King George VI, Winston Churchill and U.S. General Dwight D. Eisenhower in the Allied Expeditionary Air Force War room in the Priory's underground bunker. The German artillery binoculars on display in the Dowding room were brought back on the C-in-C's orders, having been captured from positions overlooking the beaches in France. In September 1955 the Fighter Command Silver Band performed the first Beating the Retreat ceremony by the RAF in front of the Priory. Dowding's leather-topped desk, many of his papers and other effects still occupy the room in the Officers' Mess which he used as his office, with its views across a stone balcony to the formal Italian garden below. These will remain as part of the building for its future as a museum. Anti-Aircraft Command On 1 April 1939, HQ Anti-Aircraft Command (AAC) was formed under General Alan Brooke, but on 28 July 1939, he was suddenly moved to command the British