This song was initially recorded using the Rolling Stones' mobile studio from within The Clash's rehearsal rooms at the time, the Ear Studios, in September 1981. It was later completed at the Electric Lady in New York, produced and mixed down by guitarist Mick Jones for potential inclusion on Combat Rock - at the time going under the working title of Rat Patrol from Fort Bragg.
The song was part of Jones' initial mix of the album which was rejected by the band for being too long, and though many of the songs were remixed or cut for the final Combat Rock album when it was re-edited by Glyn Jones, bootlegs exist of Jones' mix of the album, including "First Night back in London" and other songs.
Lyrically, the song appears to describe The Clash's feelings for their home country. From 1980 onwards the band had spent a lot of their time in the US recording and touring, and were subject to criticism whenever they did return to their native UK, where music critics and fans were constantly accusing them of selling out or changing their sound. So it's possible the caustic disillusioned lyrics of this song ("See my lovely town that always brings you down, where every drifter drifts, for many miles around") are a reflection on how out of place they were made to feel in their homeland. There is also an undercurrent of racism in the song, where the black taxi driver for the narrator is stopped and strip-searched, whereas the narrator isn't even touched, even though he actually does have drugs on his person ("They give him hell, they check him on the air, I sit there with the drugs in my hair").
The backing track features several clashing styles, including a reggae beat, synthetic Disco drums, and heavily echo-drenched guitars from Mick Jones in the style of the Police's "Walking On The Moon," which was released two years earlier.
"First Night Back in London" was never performed live by The Clash, probably because of the complexity of the backing track, and it featured as the B-side to the "Know Your Rights" single in April 1982. Like many B-sides it finally got an official release on the Super Black Market Clash compilation.