Burnham isn’t even in Number 10 but already faces his biggest decision as PM. Get it wrong and he could plunge Labour into another civil war, destroy his personal authority and smash the UK economy. I can’t overstate how important this is. The good news is Burnham has woken up to the scale of the threat. The bad news is he has to make an unpopular choice, and this is a man who likes being liked. Burnham has to set that aside. And lead.

The PM-designate is being swarmed by MPs desperate for promotion. Most are looking after themselves, naturally. But others are genuinely worried about the frontrunner to become chancellor. You’d think finding an upgrade on Rachel Reeves would be easy. Not in this Labour Party. All MPs want to do is spend money, then find someone to tax. Which is why the favourite to replace Reeves is the worst candidate imaginable: energy secretary Ed Miliband. And he has to be stopped.

To his credit, Burnham appears to understand the danger. So do a growing number of Labour figures, including the trade unions. They’ve seen how Miliband’s relentless pursuit of net zero destroys jobs and industry. Yesterday, I wrote how his restrictions on oil and gas drilling have devastated Aberdeen, and how his approach could cripple Britain’s economy if he gets the keys to Number 11. It will also torpedo the man who gives him the job. Andy Burnham.

Sharon Graham, general secretary of Unite, has warned against Miliband, saying as chancellor would be a “noose around the neck” of job creation. The GMB union is also furious at his wilful jobs destruction programme. If Burnham appoints him, he’ll put a powder keg under his own cabinet. And Miliband won’t blink before blowing him up.

Miliband is not a team player, unless it’s Team Ed of course. He won’t let anything stand in the way of his net zero charge. Keir Starmer and a host of cabinet members including Rachel Reeves tried to stop him, but he never listens. He talks over cabinet members. Skips meetings. Refuses to pick up the phone. And generally plays silly buggers. All the while plotting to get rid of his own PM in the most underhand way. What a man.

One MP told The Daily Telegraph that appointing Miliband would mean “you are basically handing over control, and you’ll never get it back”. He’s dead right. Just as New Labour Chancellor Gordon Brown sunk PM Tony Blair, Miliband will sink Burnham. The only way Burnham can prevent that, is not to appoint him in the first place.

Treasury minister Darren Jones just sent an indirect warning, saying the next chancellor must not try to “control” the PM. Instead, they must reassure markets, trade unions, Labour MPs and the public. Translation: don’t appoint Ed Miliband.

Burnham knows what he has to do. Pick anyone but Ed. The question is whether he has the courage to act. Right now, he’s loving the party adulation. We saw it in that ridiculous photo of MPs applauding his mere arrival at Westminster. But if he blocks Miliband, some of them will be furious. Others will breathe a massive sigh of relief. Burnham can’t please them all.

This is his first real test. Give Miliband what he wants and he’ll hand control of the government to an ideological loose cannon who won’t stay quiet. Say no and he’ll face a furious backlash from the Labour left. There is only one sensible choice. The only question is whether Burnham has the guts to make it. If he doesn’t, he’s doomed.