It’s universally accepted that energy bills are on track to keep going up. Between the supply shortages caused by lockdowns and reopenings and hardening sanctions being used to apply pressure to Russia, it’s difficult to see how this trajectory reverses. But forecasts remain varied and many factors unknown. 

Several weeks back Investec estimated average heating bills could reach £3,000. Goldman Sachs suggested bills could come close to £4,000, if Europe cuts off Russian gas completely. 

The IFS’s latest forecast, that an additional £12bn will be needed from the Treasury if it wants to protect household budgets from looming costs, may well be right. But if those cost calculations are off by a few hundred pounds per family, they will be off by billions of pounds that Sunak would need to set aside to offer financial support.

Whether the price cap is lifted in October by £500 or £1,500 would require very different policy responses from Sunak; not just in terms of how much support would cost, but also how that support is targeted and how many households are considered in need. 

One source close to the Government emphasises the point: “Anyone who claims with certainty they know how high energy bills will be in six months’ time needs to check themselves.”

Then there are supply factors. The public remains opposed to fracking, but might higher energy bills move the dial? Saudi Arabia will be wary of frustrating Russia by pumping more oil to lower the price. But if it decided to do so, the market would calm.

But these are hypotheticals; the assumption has to be that we’ll keep the status quo of shortages for some time to come. So what happens in autumn?

There is already a growing sense among Tory backbenchers that the financial burden on their constituents is too much. Will MPs demand another fiscal support package? 

“In short, yes”, says one backbencher. “We cannot be the cost-of-living-crisis party”, says another. 

In some ways, this isn’t a new dynamic between the Chancellor and the party: much of Covid was spent with MPs, Tories included, throwing requests Sunak’s way (some pandemic-related, some not) and the Chancellor explaining that this was real money that had to be accounted for.