Lobbying against Clause 28 [legistlation that aimed to prohibit local authorities from publishing material condoning homosexuality or from referring it to in state schools as an acceptable lifestyle], McKellen used his connections to buttonhole politicians, including one of Britian's most fervid anti-gay spokesmen, Michael Howard, who was later the Conservative Party leader. After a fruitless meeting, Howard requested an autograph for his children. McKellen obliged. "Fuck off! I'm gay," he wrote.
There's also some interesting scuttlebutt about how McKellen's full-bore approach to acting (some of it cited here) has alienated some co-stars, including Helen Mirren, but Lahr doesn't really follow up on it.