UK Uncut, the self-styled “anti tax avoidance” protest movement, recently struck at Barclays, whom they accuse of paying only £113 million in corporation tax on profits of £11.6 billion for 2009.

Of course, banks are still pretty unpopular at the moment, but it is only bullies and cowards who attack the private property of those they happen to dislike or with whom they disagree.

So people who vandalise and disrupt the business premises of those who, in their opinion, do not pay enough tax are tapping into exactly the same mentality as the SA brownshirts who painted “Jude” on the shop windows of Jews in the 1930s. They should reflect on how they would like it if those who dislike what they do did the same to them. Happily, only a minority have the nastiness of soul required to take out their personal frustrations out on what others have struggled to build.

That said, the “anti-tax avoidance protestors”, unlike the Nazi stormtroopers, do have a legitimate point ...or at least they are right but for the wrong reasons ...or maybe wrong but for the right reasons...

It cannot be denied that it is both stupid and immoral when the rich pay less tax than the poor. The blame for this, however, lies not with the rich but with the tax system. Governments know that overtaxing the rich is counter-productive, but cutting headline rates for the better off takes more courage than most politicians possess. So they rely instead on a tax code with lots of loopholes, of which only those who can afford expensive advisers – the seriously rich – are aware. An unsustainably high rate of tax is set on the assumption that those loopholes will be used to avoid it.

Tax policy is therefore based on a nod and a wink. Real anti-tax protestors are right to object to that hypocrisy and to campaign for the only honest and effective alternative, a simple flat-rate tax paid by all but the poorest.

Of course, the rabble who vandalise property are not interested in that. They are motivated by petty resentment, not by a determination to put in the work necessary to push for rational improvement.

This is why they prefer the soft target of private business. The root of the problem is, as usual, the politician, not the businessman – who has to operate within the system designed by the politician. Most businessmen do not like the system, but have a right and obligation, like all subjects, to arrange their affairs in the most efficient way it allows.

So attacking business is attacking the victim. However, an attack on private business provokes little response from the police or the courts, but an attack on the real villain – a government office – invites retaliation in the form of anti-terror laws, trigger-happy police marksmen, and long jail sentences, and, like all vandals and bullies, the “anti-tax avoidance protestors” lack the courage of their supposed convictions.

And, to the UK Uncut charge sheet we must add financial illiteracy. Barclays had previously made very substantial losses, which it offset against the 2009 profits in calculating its tax bill. This is not only perfectly legitimate but necessary for business to survive.

The only sustainable profit tax regime is one that is based on an economic cycle. For example, imagine a shipbuilder, who takes five years to build a ship. During production they might report an annual loss, and then declare a profit in year 5 when they complete and deliver the ship. Losses might be £10 million per year for the first four years and then £50 million in year five, making a cumulative profit for the venture of just £10 million (£50m-£40m). If that £50 million is taxed at 25%, the shipbuilder pays £12.5 million in tax – more than its profit on the whole venture.

Clearly, a profits tax that applies to losses is just loopy. But, apparently not too loopy for resentful mob that make up UK Uncut.