At the end of August 1966, the Beatles permanently retired from touring and pursued individual interests for the next three months. During a return flight to London in November, Paul McCartney had an idea for a song involving an Edwardian military band that formed the impetus of the "Sgt. Pepper" concept. Sessions began on 24 November at EMI Studios with compositions inspired by the Beatles' youth, but after pressure from EMI, the songs "Strawberry Fields Forever" and "Penny Lane" were released as a double A-side single in February 1967 and left off the LP.