James Daley: They've got to pick a pocket or two

We've all heard the tragic stories of people turning to crime in desperation when they run out of money. Petty theft, burglary, perhaps even armed robbery – anything to make ends meet, which will prevent them from having to admit to their pecuniary failures and suffer a loss of face to their families and friends.

But I honestly never thought I'd see such behaviour from the Chancellor of the Exchequer and the Prime Minister – two men for whom pickpocketing their loyal supporters seems now to be an ordinary part of day-to-day life.

Although they would surely command more respect if they simply fessed up and admitted that they'd accidentally got themselves into a terrible financial situation, they continue to insist that the public finances are in a healthy state while persisting with their petty thievery on the side, stealing a few extra pounds from taxpayers whenever they're not looking.

Over the past few weeks, yet another handful of sneaky revenue-raising tricks have been uncovered in the small print of the Finance Bill – the document that brings the measures announced in the annual Budget into law. And, once again, it has been left to opposition MPs and the media to explain the full repercussions of these measures to the public.

One to emerge this week was the news that people who have overpaid tax will now only be able to reclaim it as far as four years back. This may sound like time enough, but when you take into account that almost half of all tax reclaims go back over six years, you begin to realise that this is no less than robbery. This is, quite simply, not the Government's money to take.

Worse still, many of those who overpay tax are pensioners, who have perhaps ended up on the wrong tax code through no fault of their own. It often takes the intervention of a family member to point out the error, and in these cases it is quite possible that the overpayments will go back more than four years.

To add insult to injury, this year's Finance Bill also contains new measures to increase the penalties which the HM Revenue & Customs department can land on taxpayers who don't pay enough tax. Although there is currently considerable leeway for people who underpay tax accidentally, the new laws will give the Revenue the power to hit even those who completed their returns in good faith.

Both of these new measures are sure to leave thousands more taxpayers losing out at the hands of the Revenue's own incompetence. Many of those who do not file their taxes correctly do so because the Revenue makes the process so mind-numbingly complex. Equally, most of those who overpay tax do so because of Revenue errors, not their own.

Then there's the changes to Vehicle Excise Duty (car tax to you and me), which will more than double for some families next year because their cars are not eco-friendly enough. This might be fair enough if they'd bought the cars yesterday, but many of those who will be hardest hit bought their cars years ago – without any hint that they might get landed with a super-tax somewhere down the line simply because they chose the wrong model. Environmental taxes should be used to change people's behaviour, not to penalise them for decisions they made years ago.

It's bad enough that a Prime Minister who made his name on economic competence is now presiding over an economy that is sliding towards recession. But we are where we are. Brown and Darling need to stop the bluffing and pickpocketing and start being honest about their initiatives to fix the public finances. Their reputations can't get any worse, and – who knows? – honesty might just win them some respect.