Who might replace Simon Case as Cabinet Secretary?

The rumour swirling around Westminster is that there will soon be a new Cabinet Secretary, the most senior civil servant position. Politico reported that current Cab-Sec Simon Case is being advised to step down for health reasons at the end of the year, providing an opportunity for Keir Starmer to fill the position with his person. But who might that be? Who are the runners and riders to become one of the most powerful people in government? Katy Balls speaks to Henry Newman, former advisor to Boris Johnson and editor of the Whitehall Project substack.  Produced by Oscar Edmondson.