 Complete the following phrase:  When the Royal Air Force left Hendon in the 1960s, the Metropolitan Police decided to rebuild the 1934-1939 college, which was renamed after Sir Robert Peel and reopened as the Peel Centre by Queen Elizabeth II on 31 May 1974, forty years to the day after her uncle opened the original Metropolitan Police College. The Queen has returned three times since then: in 1977 to open the new Hendon Gym, on 21 October 2001 she dedicated a memorial to Metropolitan Police officers and staff who lost their lives on duty, and on 3 January 2005 she visited the Casualty Bureau dealing with British nationals missing after the 