So now we know the four candidates who are competing to be the next Labour leader, and I must admit I’m struggling to work out whether any of them has the “X-Factor” needed to make the leap from party leader to prime minister.

Apart from Jeremy Corbyn, who is a throwback to the Bennite Lefties who kept the party out of power for a generation in the 1980s, it’s difficult to really understand the subtle differences between Messrs Burnham, Cooper, and Kendall.

All seem to have realised, somewhat belatedly, that Ed Miliband was a liability, not an asset, at the General Election.

And all seem to have realised, very belatedly, that going on about “fat cats” and picking fights with business was going to alienate the self-employed and those who aspire (sorry to use that word) to make a better life for themselves.

I must admit that I’m not convinced that any of those standing for the leadership will be able to beat the Tories in 2020.

Andy Burnham and Yvette Cooper were members of Gordon Brown’s cabinet and will remain tainted by charges from the Tories that they failed to make preparations for the downturn that was always inevitable.

It is ludicrous to blame the last Labour government for the crash. It was a global phenomenon that started in the US with the collapse of sub-prime lenders. But if it hadn’t started there, it would have started somewhere else.

The history of economics tells us that boom is always followed by bust which is eventually followed by another boom. Labour’s mistake was not causing the crash, it was claiming: “We’ve put an end to Tory boom and bust.”

Both Andy Burnham and, especially, Yvette Cooper were part of the Labour cabinet that made that claim. Given that fact, is it any wonder that their economic understanding is questioned?

Liz Kendall is not tainted by membership of the last Labour government, she was not elected as an MP until 2010, but when I hear her comments I wonder what she has to offer the party except for a withering condemnation of the previous leadership.

All of which leaves me wondering who there is who can attract the floating voter to Labour? Can any of these do what Tony Blair did and get the young professionals and the small business owners to vote for the party?

Who can persuade the IT workers and well-paid graduates in Ipswich to vote Labour? Who can persuade voters that it is not just a party for the under-privileged and down-trodden?

Let’s be honest though, when there’s a change of power at an election it is not really because one party wins so much as the other party has lost. Just occasionally (like 1945 or 1997) the two coincide. Can Labour do it again – we’ll have to wait five years to find out.