Rhythm track recorded January 19, 1967 by The Beatles.
Hit album version released June 1, 1967 by The Beatles.
From All the Songs: The Story Behind Every Beatles Release:
“The production of this song was epic. On the day of the first session, January 19, the song was not yet finished. The group recorded the basic rhythm track in a simple manner (piano, acoustic guitar, bass, drums, bongos and maracas). John’s voice, wrapped up in a heavy echo, was particularly moving. Instead of a traditional countdown, John called out ‘sugarplum fairy, sugarplum fairy.’ The whole team felt emotion. Audio engineer Geoff Emerick remembers shivering as he heard this.
“The Beatles decided to leave twenty-four beats blank after the first and the second ‘I love to turn you on’, because they did not know at the time how to fill the space. It was Mal Evans in charge of counting the beats, and you can hear him mixing up the numbers. Originally his voice was supposed to disappear, but it was impossible to delete it – as well as the alarm clock ringing to indicate the end of the section! It was purely random that the ringing coincided with Paul’s bridge (‘Woke up!’).”
The Beatles, “A Day in the Life” album final mix (1967):