Reeves should ignore the howls of protest and tax EVs to make up for losing fuel duty revenues

If you want a document to give you sleepless nights, the Office for Budget Responsibility's biennial fiscal risks and sustainability report is a go-to publication.

- Nils Pratley

This is the one that looks to the horizon and covers everything from demographic trends to state pension promises to the climate crisis.

The headline finding in July's version was a true jaw-dropper. The UK's public finances are on an unsustainable long-term trajectory because government debt would rise to a remarkable 270% of GDP by the early 2070s - up from almost 100% today - if current policies were left unchanged, the OBR said.

The "if nothing changes" qualification is important because some of the risks to the public finances are so blindingly obvious - and have been for ages - it is astonishing successive governments have ignored them.

One is the certainty that government income from fuel duty will dwindle to next to nothing once we're all driving electric vehicles.

The July document spelled out the arithmetic. From expected revenues of £24.4bn from fuel duty in 2024-25, a halving is projected by the 2030s and receipts will be close to zero by 2050.