He could, theoretically be removed by the House without the need for a GE, though quite how is an odd conundrum, not in the least because it would practically mean the PLP proposing a Conservative govt at this juncture.
The process for that is fairly simple – a vote of no confidence lost means that the incumbent PM is then given a brief period to ‘regain the confidence of the House’. If he fails to do that, then in theory another MP, in this case Conservative, given the majority, could approach the Queen and ask to form a government. If this MP says he/she could command the confidence of the majority, then the Queen would offer Royal Assent.
A general election would follow only if no other politician was in a position to win a confidence vote. It’s associated with VONC mainly because they tend to happen to governments with very slim majorities or minority governments, where there is no immediate prospect of anyone winning another one.