It is essential that the UK's next PM is a skilful leader

Theresa May will go head-to-head with Andrea Leadsom in a ballot of Conservative Party members, that will be decided at the end of the summer.

This is an internal Tory matter, but it is of grave concern to the rest of the nation.

The next leader will of course be prime minister but even that is not the most important fact of the outcome of the leadership contest – after all, an incompetent inhabitant can be removed from Downing Street soon enough and then become a footnote in history.

But this particular PM will be plunged straight into complex negotiations with the European Union on the nature of the United Kingdom’s future relationship with the EU, the outcome of which will have ramifications for decades to come.

As the distinguished economist John Simpson explains in this newspaper, that outcome could be anything from an amicable separation to a bitter and difficult relationship.

Some of the EU has already made clear that it is in no mood to strike a good deal for the UK. Apart from anything else, this would make departing the EU more attractive to other member states.

It is often said that the UK is an important trading partner for the EU because it exports more to us than we do to them. That is true, but misleading – our trade to them is a much higher percentage of our overall economy than their trade to us is a percentage of their vast overall economy.

Theresa May has already shown that she can unite Brexiteers and Remainers. She has diplomatic skills and she has held down one of the hardest briefs in politics – the Home Office – for six years.

Ms Leadsom, who only became an MP in 2010, now has a two month opportunity to prove whether she has comparable qualities.