In this “budget for marginals” series, we’ve already had deficit reduction and a tax cut – which leaves, for the sake of neatness, a spending proposal. Not that taxpayers’ cash should be spread around liberally, of course. But there are still some items of spending that make more sense, economically and politically, than others.

One of these, generally speaking, is capital spending. Most folk within the Coalition now accept that they should probably have stuck closer to Alistair Darling’s capital spending plans, and instead cut more money from departmental budgets in that original Spending Review. Indeed, George Osborne has since tried to make amends: starting with the Autumn Statement in 2012, he now consistently calls on ministers to identify additional savings, so that the money can go towards infrastructure.

But what infrastructure? Here, the Government already has a plan: a National Infrastructure Plan, to be precise. This contains various provisions for the country’s roads, train tracks, air ways, flood defences, etc., etc. It’s necessitated, on average, £45 billion of spending a year. It’s not insignificant.

But, even putting aside the extended time lag from design to completion for some of these projects, the National Infrastructure Plan could deliver more. What I’d like to see, in particular, is proper consideration given to road pricing. As the Institute for Fiscal Studies has pointed out, today’s methods for drawing money out of motorists are on a downwards curve: “revenue from motoring taxation is set to drop by £13 billion a year by 2029.” New – and fair – ways of raising cash for the maintenance of Britain’s roads will need to be found.

Sadly, though, modern political history is littered with examples of ministers backing away from road pricing – including Osborne himself, as recently as last December. Besides, we’re meant to be proposing Budget policies for the marginals, and I’m not sure that making people pay as they go will prove particularly popular.

(That said, however, road pricing isn’t unambiguously unpopular. It often depends on the type of road pricing that’s being proposed, and what the money will go towards. Some polls, for instance, find 29 per cent support for more motorway tolls, against 21 per cent opposition. To quote the IFS again: “Pointing out the likely benefits, including reduced congestion and the fact that fuel duty would be substantially cut, could also help to change the public mood.”)

So how about more money for quick and relatively simple road renovations, such as filling in potholes? I know I mentioned this on Monday. And I know that the Government just stumped up £146 million, on top of what it already provides, for removing these pockmarks from our roads. But this was focused on those areas affected by the floods. Councils reckon that a further £10 billion is required to fix all potholes, everywhere. That’s surely too much for the Chancellor to countenance, but some of it might be clipped out of departmental budgets. As I said before, there’s plenty of evidence that this would be a popular policy – perhaps more popular than further cuts to fuel duty, and cheaper too.

Of course, it’s not entirely straightforward. Local authorities tend to deal with potholes, so they would have to be trusted to act once the extra cash is wired to them. But that’s where transparency could come in handy. Name ‘n’ shame the local authorities who register the most pothole-related complaints. Let tarmac win the day.