Take a look at a football manager, any football manager, and know this: there is a number after his name. He doesn’t know it; his family doesn’t know it; his employer doesn’t know it. Neither do his players nor any fans.

In fact, the only people who do know the number are me, and the BBC presenter, Dan Walker. It’s something we work out between us every now and then. The number is this: it represents the number of consecutive games he can lose before he gets the sack.

For example, in the Premier League, as I write, Huddersfield are bottom of the table. I’ve got their manager, Jan Siewert, at six. “Why that many?” I don’t hear you ask. Well, his side looks doomed to relegation anyway so there’s not a lot of point giving him the boot. And he’s not long in the job anyway, so that allows another point or two on the Chiles-Walker Index. If, however, he were to lose the next six, then they’d be so doomed there’d be no point in keeping him. If he loses Huddersfield’s next game, away at West Ham, then I think Dan and I will give him a CWI of five. However, if they were to win that game I think Herr Siewert might retain his CWI of six, or even extend it to seven. Dan and I will have to have a serious conversation about this if it comes to pass.