This is on Wikipedia, but there's no source: "...a jibe at an unnamed group who wear Burton suits, taken by many to be The Jam (though in an NME article of the time, Strummer claimed the actual target was the power pop fad hyped by journalists as the next big thing in 1978) and the lyric concludes that the new groups are in it solely to be famous and for the money."

I also thought it was aimed at the Jam, as it was right after they (the Jam) announced they were voting conservative.

However, looking back... well, the Clash also turned rebellion into money. They of course kept themselves more real, and they were way less packaged, but still.