// @Gromit, so you think Corbyn will be PM then? //
If there is an election now, it would be a hung Parliament. The Coalition partner would insist to the Conservatives that Boris had to go. Likewise, if Labour were in a coalition, the partner would not accept Corbyn.
If there is a General Election in the longer term, say next year, then both Corbyn and Johnson will have been removed by their respective Parties.