Although written by John Lennon in 1968, Polythene Pam wasn’t recorded and released until the following year, when it was included as part of the long medley on the Abbey Road album.

Polythene Pam was recorded as one with Paul McCartney’s She Came In Through The Bathroom Window. It was the only time two separate songs by the two writers were recorded as one.

The song recounts, with some poetic licence, the tale of a Liverpool scrubber with an almost comical fetish. Sung in a thick Scouse accent for earthy authenticity, it harks back to The Beatles' early days performing in Merseyside’s seedier venues. It also resurrects the group’s ‘yeah, yeah, yeah’ refrain from the days of She Loves You.

The character of Polythene Pam is believed to have been drawn from two women from different times in The Beatles' existence. The first was Pat Dawson (née Hodgett), a Liverpudlian fan from the group’s early days, who was known as Polythene Pat due to her somewhat improbable love of the substance.

I started going to see The Beatles in 1961 when I was 14 and I got quite friendly with them. If they were playing out of town they’d give me a lift back home in their van. It was about the same time that I started getting called Polythene Pat. It’s embarrassing really. I just used to eat polythene all the time. I’d tie it in knots and then eat it. Sometimes I even used to burn it and then eat it when it got cold. Then I had a friend who got a job in a polythene bag factory, which was wonderful because it meant I had a constant supply.
-Pat Dawson

The second woman was the girlfriend of English beat poet Royston Ellis, for whom The Beatles had performed as a backing band in Liverpool in June 1960. The group remained friends with Ellis for some years, and in August 1963 John Lennon had a memorable encounter with Ellis and his girlfriend Stephanie.

That was me, remembering a little event with a woman in Jersey, and a man who was England’s answer to Allen Ginsberg, who gave us our first exposure – this is so long – you can’t deal with all this. You see, everything triggers amazing memories. I met him when we were on tour and he took me back to his apartment and I had a girl and he had one he wanted me to meet. He said she dressed up in polythene, which she did. She didn’t wear jackboots and kilts, I just sort of elaborated. Perverted sex in a polythene bag. Just looking for something to write about.
-John Lennon

The incident actually occurred in Guernsey following The Beatles' concerts on 8 August 1963. Ellis and Stephanie invited Lennon back to their rented flat where the three wore polythene and shared a bed out of curiosity about kinky sex.

We’d read all these things about leather and we didn’t have any leather but I had my oilskins and we had some polythene bags from somewhere. We all dressed up in them and wore them in bed. John stayed the night with us in the same bed. I don’t think anything very exciting happened and we all wondered what the fun was in being ‘kinky’. It was probably more my idea than John’s.
-Royston Ellis

The Beatles recorded a demo of Polythene Pam in May 1968, at Kinfauns, George Harrison’s bungalow in Esher, Surrey. The song was considered for inclusion on the White Album, but it wasn’t recorded until over a year later.

The Kinfauns demo was eventually released in 1996 on Anthology 3. In it, the line “She’s the kind of a girl that makes the News of the World” is replaced by “Well it’s a little absurd but she’s a nice class of bird”. There are also variations in the song’s chords.

On Abbey Road’s Mean Mr Mustard, the line “His sister Shirley works in a shop” was changed to “His sister Pam…” to create an impression of narrative continuity. While recorded separately, the two songs appear back-to-back on the album, having been recorded in the same key and edited together without a gap.