Almost every year the most-read story on the Guardian website on budget day is “What it means to you”. Readers want to see a quick ready-reckoner on what the tax changes mean for their pay, plus the main points that might have some impact on their life.

So every budget day, us hacks and accountants across the country spend a feverish few hours trying to put together instant at-a-glance tax calculators and tables.

This year was especially hectic, as the changes to the personal allowance were the centrepiece of the budget. Hammond proclaimed that it meant £130 extra for the low-paid. “A tax cut for 32 million people … £130 in the pocket of a typical basic rate taxpayer,” he said in the Commons.

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It was pure political spin. Yes, those words were absolutely correct. But the main benefit of the tax cut went to the 4 million well-paid, with an £860 gain for someone on £50,000 a year. We spotted this quickly and posted our story up as soon as possible.

It would have gone up more immediately, bar one major problem. Where were the national insurance rates for 2019-20 to sit alongside the income tax rates? We searched the slew of budget documents that are always released the moment the chancellor sits down. Nothing. Only a call from a contact with inside knowledge enabled us to go ahead with a story that added in the impact of the new NI rates, cutting the typical gain to £520. Many other newspapers failed to spot it, instead publishing follow-ups the next day to explain the hit from NI.

This is an absurd carry-on. Hammond and his special advisers can spin however they like, but the civil servants in the Treasury and HMRC answer to the people, not to a political party (and Labour is as bad as the Conservatives on this topic). That they can issue budget personal tax documents that obscure rather than enlighten is evidence of how far the service has sunk.

Page one of the budget documents should give a straightforward breakdown of how the new tax rates proposed by the government will affect individuals in the next tax year. It’s what the people want to know, and it’s extraordinary they are not published already. In print, there should be a table of income bands with tax and NI published immediately after the speech. Online, there should be a calculator where anyone can log on and calculate the impact on them and their family.

I can assure the chancellor the Treasury website would never be more popular.

p.collinson@theguardian.com