My first choice would have been In The Light Dub, but that's already gone, so I thought I'd go with Blackbeard's I Wah Dub. It was a very big record for me & my boys when it came out in 1980, and it seemed to be a big record with many UK post-punk types generally. Basically, Dennis Bovell goes off on this, as if he was trying to make the wildest, most out-there, most technologically here-and-now dub record he could, and the cover art taps into that whole afro-futurist thing evident in Parliafunkadelicment, Sun Ra and so on. Adrian Sherwood did something broadly similar around the same time with Creation Rebel's Starship Africa, which went even further out, to places sonically nearer to Ornette Coleman or electric Miles than to reggae. Contemporaneously, this originates from around the time Bovell was producing The Pop Group and The Slits, and I seem to remember a few dub connoisseurs getting a bit sniffy about it. The suggestion was that it was a gimmicky, commercial record rather than a serious dub album, purposely designed to appeal to all the punk-rock kids who'd begun turning up at Matumbi shows. Perhaps it was, but I don't really care about that - it's got as much character and musicality as any other great dub record I can think of, and it stands up to repeat listening.
https://www.youtube.com/watch?v=2j1rrToxNFQ
Interesting take-that-shit-to-the-brits fun fact about this album; in the early years of EastEnders, this album was regularly used as diegetic music in the show. Whenever you heard generic reggae music playing in the background of a scene, it was invariably a track from I Wah Dub.