Keir Starmer has resigned as Labour leader and will stand down as prime minister once a successor is chosen, throwing UK politics into another period of instability. Andy Burnham is the frontrunner and could enter Downing Street quickly if no serious challenger emerges. For investors, the key question is whether a Burnham government keeps tight control of borrowing or shifts towards higher public spending to tackle weak growth, strained services and the cost of living. Any looser fiscal stance could keep pressure on gilts and make the Bank of England more cautious on rate cuts if inflation risks rise. Markets were relatively calm: sterling recovered after earlier weakness, gilt yields edged lower and the FTSE 100 and FTSE 250 were broadly steady, suggesting investors welcomed the prospect of an orderly transition