A little excerpt from an article by George Monbiot.

"It's arguable that the UK government does not have a spending crisis; it has a tax avoidance crisis. Official accounts suggest that the tax gap amounts to £42bn(2). Richard Murphy of Tax Research has demonstrated that this figure cannot be correct, as it contradicts other government statistics. He estimates that avoidance now amounts to £25bn a year, evasion to £70bn, and outstanding debts to the tax service to £28bn: a total of more than £120bn(3).

That's roughly three-quarters of the budget deficit(4). It's equivalent to 80% of the UK's revenue from income tax(5). By comparison, benefit fraud, which both the government and the rightwing press emphasised in order to justify the cuts, amounts to £1.1bn a year(6). No one would claim that all this missing money could be recovered. But even if only 20% were clawed back, the most damaging cuts could be reversed."

The rest of the article can be found here