For month after month, week after week, sometimes day after day, we have chronicled the unravelling of Sir Keir Starmer's government. Nonetheless, it still prompted a sharp intake of breath on Monday morning to be standing in Downing Street yet again, awaiting another prime minister publicly reading the last rites on their time in the highest office. This wasn't a leader brought down by scandal, as Boris Johnson was, nor economic calamity, as Liz Truss was.