Marr branded the government's cutbacks to public services in Manchester -- which include axing special school bus services for children with disabilities -- "inhuman."
"Seeing as you're in our city I'd just like to ask you about the Brentwood school for disabled children in South Manchester," he said. "Do you know what it's like for an autistic girl to have to get on a public bus to go to school every single f---ing day?"
He also dedicated his cover of "Crash" by The Primitives to the British leader, singing the song's lyrics, "shut your mouth 'cos I'm not listening any how, I've had enough of you, enough to last a lifetime through".
This isn't the first time Marr has clashed with Cameron. On hearing that the politician was a fans of The Smiths, the guitarist in 2010 banned him from liking his old band, tweeting "David Cameron, stop saying that you like the Smiths. No you don't. I forbid you to like it."
Johnny Marr: The Music That Made Me
Marr's management even suggested that Cameron had requested to attend the Manchester gig, tweeting that they had received a guest list request from a "HIGH profile person who's working in Manchester this week."
Alongside Marr, The Conservative Party conference was met with widespread protest across Manchester with thousands turning out on the streets to call for an end to austerity economics, the privatization of public services and inequality.
The conference came just weeks after Cameron was at the center of a social media-stirring accusation that he had once put a "private part of his anatomy" into a dead's pig mouth as part of a college initiation ceremony, echoing a story about a fictitious prime minister in the critically-lauded drama series Black Mirror.
This article originally appeared in THR.com.