Benjamin Zephaniah has made a passionate defence of Jeremy Corbyn, who faces a media "against him" and Labour MPs "plotting against him".
The poet and writer spoke up for the embattled Labour leader on BBC's Question Time ahead of the results local, London and devolved national elections, and said Corbyn is up against "dirty" politics and "hostile" MPs.
Corbyn could face a coup on a disastrous night for Labour.
Some MPs, described variously as the party's right, Blairites and moderates, claim Labour needs to be winning 400 seats - typical of an Opposition party on its way to government.
But John McDonnell, Shadow Chancellor and a key Corbyn ally, has been arguing the party is making "steady progress" if it closes the gap on the Tories since the General Election.
Corbyn's leadership has also been engulfed by an anti-Semitism row after the suspension of MP Naz Shah and former London mayor Ken Livingstone, who is also close to the Labour leader.
But Zephaniah claimed Corbyn was facing a "very hostile climate".
"The Press is against him, people in the party plotting against him. I've known him for years, and I know he's a brilliant campaigner.
"That he cares about things passionately. He's the kind of person that shouldn't actually be in politics, because politics is so dirty.
"Last week, apparently, he was supposed to be an anti-Semite. He's the only mainstream politician I know who has been arrested for anti-racism."
David Dimbleby presented the debate from Manchester on Thursday evening.
Also on the panel were Conservative former Chancellor Lord Lawson, Labour's Shadow Energy Secretary Lisa Nandy MP, chief executive of Ryanair, Michael O'Leary, and Daily Mail political editor-at-large Isabel Oakeshott.