Odds on a Corbyn premiership?
Fairly unlikely, barring a black swan event, since he's *still* behind in the polls despite the current mess that the Tories have got themselves into. He regularly gets beaten by the 'Don't Know' option when it comes to polling on preferred PM, him or Theresa May. The Tories have descended into infighting, they've been in power for eight years, Theresa May is a pretty unpopular PM and they're pursuing a divisive policy goal (Brexit) yet he still can't beat them.
For him to become PM he'd probably have to form a coalition government, and I'm not sure who would want to partner with him in a hard-left government with a whiff of antisemitism about it. Probably only the Scottish nationalists, but their popularity has been in decline and will probably win even fewer seats than they did in 2017. He'd also go up against a far more popular Tory leader in any future election.