Editorial: ​Keir Starmer is going as prime minister but the big UK problems still remain for his successor

​​Keir Starmer became briefly emotional when he announced that he was stepping down as prime minister.

This flash of vulnerability came as he stood in Downing Street, paying tribute to his wife and children.

Some observers thought it showed a human side to a leader who has been criticised for being robotic. Others criticised it as a sign of weakness that you would never see in a leader such as Donald Trump.

Whatever way people respond to the human aspect of the exit of Sir Keir from the head of government, the problems that his successor – almost certainly Andy Burnham – faces have not changed one iota. He becomes the seventh PM in a decade.

The principle difficulty is that Labour has a landslide in parliament with a mandate that makes it almost impossible for them to do some of the things that need to be done. One thing that seems to be essential is a reduction in the UK’s indebtedness, but this will involve either tax rises on top of the tax rises that have already proved so unpopular – such as in national insurance contributions by employers, or attempted increases in inheritance taxes for farmers – or cuts.

Cuts are even more unpopular than tax rises.

Some economists think that a fiscal crisis is all but inevitable.

The only feasible path forward is that Mr Burnham has a respect amongst leftwing Labour members that will enable him to be bolder than Sir Keir felt able to be, as a relative newcomer to politics.

There are other huge problems with regard to defence and mass immigration, where Mr Burnham’s room for manoeuvre seems similarly constrained.

Meanwhile, Stormont has huge problems. Will Mr Burnham be just as inclined to appease the Irish government, and nationalists generally, as was Sir Keir?

There is great uncertainty ahead, for Northern Ireland and the rest of the UK.