It's become a familiar sight in British politics - the lectern outside 10 Downing Street, ready for another resignation speech.

On Monday morning, Sir Keir Starmer became the sixth prime minister to stand down in almost a decade, despite on paper commanding a huge Labour majority.

So, why was his departure inevitable? And what will be the Starmer legacy following his two years in office?

Niall Paterson is joined by Sky's political correspondent Rob Powell.