Is Sadiq Khan the new Boris Johnson - a London leader setting his sights even higher?

Mr Khan has made it very plain that he wants Labour to appeal to a wider constituency than it currently enjoys. Translation: “Look at what I managed to do in London and have a think about it, Corbynistas. I may make myself available if the need arises"

BSadiq Khan during his swearing-in ceremony at Southwark Cathedral in central London on May 7, 2016. (AFP/Getty Images)

Political symmetry is always an intriguing phenomenon, and we now have an intriguing example to ponder: is Sadiq Khan the “New Boris Johnson” in more ways than one?

As the new Mayor of London, Mr Khan's working class background - well publicised - could hardly be more different to Boris Johnson's. Nor his politics - witness Mr Johnson's reckless and tasteless attack on President Obama's heritage. But one thing they do have in common is an ability to appeal to voters far beyond their traditional base. Indeed no candidate could become Mayor of the capital unless they could do so. There is an element of charisma required too, and while Mr Khan lacks the overgenerous quota granted to Mr Johnson, his quiet confidence is one of his appealing and impressive assets. All through Zac Goldsmith's “dog whistle” campaigning, Mr Khan kept his cool. Cool goes down well in London; trying to imply Mr Khan might sympathise with people who blow up buses did not.

But just as Mr Johnson was and is, though with sliding credentials, seen as a potential new leader for his party, so now is Mr Khan, hardly settled into his new job, being talked about as the successor to Jeremy Corbyn. Like Mr Johnson, Mr Khan uses hints and choreography to make the point, though the effect is hardly subtle. He has been rarely glimpsed with his party leader, who had to make do with a photocall with the new Mayor of Bristol instead of Mr Khan - and Mr Khan has made it very plain that he wants Labour to appeal to a wider constituency than it currently enjoys. Translation: “Look at what I managed to do in London and have a think about it, Corbynistas. I may make myself available if the need arises.”

Of course such manoeuverings and political chatter are dangerous. Ask Michael Heseltine, Michael Portillo, Alan Milburn, David Miliband and scores of others who assumed the title of “next leader”. Those around Mr Corbyn have the party membership on their side. Unlike football managers, Mr Corbyn seems to become more liked and respected among his fans the more he loses. Perverse, but, given his party puts principle ahead of power, not so surprising.

Much also depends on how Mr Khan performs in office. In France and the US, city, regional or state government is an accepted route to the highest office. If you've been a fine Mayor of Paris or effective Governor of Texas or Arkansas you can rightly aspite to national leadership. So for his sake and that of his party,and indeed his city, Mr Khan might be well advised to just get on with the job. If he achieves things, his time will come.