Sir Keir Starmer vowed to prove his doubters wrong as he faces mounting pressure from Labour backbenchers to resign or set a timetable for his departure, despite his insistence he will not quit following a set of bruising local election results. The discussion surrounding his political future has drawn comparisons with Labour predecessor Sir Tony Blair’s exit from No 10. Crucially, however, there is no obvious successor to Sir Keir, unlike Gordon Brown’s clear path at the time. Catherine West had previously said she would challenge Sir Keir for the party leadership as early as Monday afternoon in an attempt to force the Cabinet to put forward a replacement as prime minister. But following a speech in which Sir Keir said he would not “walk away”, the former Foreign Office minister said she would now canvass support within the party for the Prime Minister to set out a timetable for his resignation by September.…