No Labour PM has been ousted by the party. Wilson and Blair didn't have to resign.You can currently get odds of 5/1 for Starmer to step down this year which suggests it's far less likely than you think. That doesn't mean it definitely won't happen but if something was truly in the air then the bookies would be pricing it in for sure
Given the accusations about his U-turns, maybe he will belatedly see which way his MPs are going and follow them.

