 Two synchronised tape copies of a finished recording were played simultaneously into a third master recorder, and by manually retarding the rotation of one of the two tape reels by pressing on the flanges, a skilled engineer could subtly manipulate the phase difference between the two sources, creating the lush 'swooshing' phase effect that sweeps up and down the frequency range.The original single version was mixed and mastered in mono, and the phasing effect is more pronounced in the mono mix than in the later stereo mix.The song was first conceived and largely written by Ronnie Lane, who had been reading a leaflet on the virtues of Oxford which mentioned its "dreaming spires".