Post-punk band Squeeze used a performance on the BBC's Andrew Marr Show to protest against fellow guest David Cameron.
They changed the lyrics of hit Cradle to the Grave to sing the line: "There are some here who are hell bent on the destruction of the welfare state."
Mr Cameron had been interviewed on the show and was watching the band's closing performance.
The band later tweeted about its "third verse message" for the PM.
Squeeze, formed in South London in 1974, reached the peak of their popularity in the late 1970s and early 1980s with songs including "Cool for Cats", "Up the Junction" and "Tempted".
In the adapted version, front man Glenn Tilbrook also added the line: "I grew up in council houses, part of what made Britain great".
A BBC spokeswoman said producers had not been aware of Squeeze's protest beforehand.
Downing Street said it was not commenting on the performance.