Sir Sadiq Khan has warned Sir Keir Starmer that his "10 years in power" ambition is not realistic in another damning blow to the Prime Minister's plans to remain in No10. It comes after Sir Keir insisted he will not step down as Prime Minister and outlined his desire to remain in the position for a decade.Labour MPs are now assembling in their droves to demand the Prime Minister's resignation after the party's dismal display at the local electio…