On 20 and 21 July 2007, fans arranged the celebration of the 40th anniversary of the success of "A Whiter Shade of Pale", and invited the band to play. This took the form of two concerts at St John's, Smith Square in London. 20 July saw Procol Harum play a mixture of songs from their early days through to the début of a couple of new songs, "Sister Mary" and "Missing Persons". The following night 'Gary Brooker and Guests' performed a fixture of obscure songs by Brooker–Reid that had either never been recorded, never been performed live before or were significantly different from the versions they recorded.