Comment: Darling at the petrol pumps

It is heartening to learn from our interview with the Chancellor, Alistair Darling today that he regularly gets badgered by constituents as he is putting petrol in his car. "It's a good experience for a Chancellor to fill his car up - it's one of those occasions you cannot get away from someone who wants to have a word." It certainly is desirable that a prominent government minister should be in a position to be badgered by genuine members of the public. And perhaps it was as a result of his constituents' views - or possibly the road hauliers' threat to step up their protests - that he makes clear in our interview that he will be reconsidering the planned 2p rise in petrol duty this autumn. Fuel duty, he says, "is something you pay every week, not once a year, and that is something that we in government are very focused upon."

By contrast, he seems to be standing by his commitment to a higher annual tax on big cars - a controversial measure since it will affect cars purchased years ago. Higher taxes on big cars purchased now are completely justifiable - but the tax as it stands will fall not just upon ostentatious big models but on seven-year-old family cars. That, inevitably, will cause resentment.

Mr Darling does not try to pretend that the abolition of the 10p tax band was anything but a mistake. But the real problem was abolishing it without properly considering the impact of the change on low earners. He might have added that the changes to capital gains tax and non-doms were equally ill-advised. In this context, the Tories are proposing that any technical changes to the tax system should be made public six months before a budget - that way, any unforeseen repercussions can be avoided. Indeed, the party also intends that an all-party committee of MPs and peers should examine government proposals to raise revenue. If this means that there are fewer unintended bad consequences from changes to the tax system it would be a very good thing.