WHAT does Gary Barlow think tax is for? The pop star appears to understand the idea of public duty. He is known as a dedicated fundraiser for charity. For years he has organised events that raised multi-millions for the benefit of others. But when it comes to dipping into his own pocket to make a fair contribution to society, it's been another matter.

Doesn't he realise tax is the bedrock of our society? It is how we pay for our welfare state, the NHS, our children's education, the police, our roads and pretty much all the infrastructure we rely on. It is a more dignified and effective way to look after everyone's needs than charity can ever be.

Certainly we all find it painful to part with a chunk of what we have earned - to send it south to the Treasury. But that distress is offset by the knowledge we contribute on a sliding scale. We give as a proportion of what we earn. Those at the bottom of the economic heap are excused while those at the top bear a heavier burden.

Or do they? In Barlow's case it seems not. The man lauded by fans and honoured by Buckingham Palace for generating money for the disadvantaged was, at the same time, "aggressively" avoiding what he owed in tax.

With two other members of Take That and the group's manager, he had a £66million investment in a convoluted tax-planning scheme called Icebreakers. None of 51 Icebreakers partnerships made a profit. Instead the losses they accrued could be set against tax. At the tribunal which ruled they must repay the Treasury, the judge said: "The predominant purpose of entering the scheme was to achieve a tax saving."

When the news broke there were calls for Barlow to return the OBE he received in 2012 for his charitable work and his contribution to entertainment. Some said he should be stripped of it. Margaret Hodge MP, chairwoman of the public accounts committee at Westminster, suggested Barlow might want to show contrition by giving it back.

The Prime Minister was asked for his view yesterday morning on live television. It was a golden opportunity to ram home the message he delivered when comedian Jimmy Carr was caught in a similar exposure. Then Mr Cameron called Carr's actions "morally wrong".

Instead of repeating that message, Mr Cameron cavilled. He said he opposed the tax avoidance but felt Barlow should retain his OBE because of his charity work and the huge amount he had done for the country.

The moment was lost as viewers registered with a certain world-weariness that Barlow is a Conservative Party supporter. And so we sink another notch. It makes me livid.

Do you recall (as I do) how often Conservative ministers have railed against the unfair plight of hard-working tax payers who get up early to go to work while their lazy, benefit- claiming neighbours' curtains remain closed?

Mr Cameron's government had no hesitation in vilifying people at the bottom of the heap. Shouldn't the same rule apply to those at the top - with knobs on? How admirable is it to stockpile private wealth by skimping on your rightful contribution, when real hardship is all around?

We've seen Starbucks, Amazon and other big companies shamed. Now we are seeing celebrities in a harsher light.

Bear in mind that right here in Scotland, the Trussell Trust reports a five-fold rise in demand for emergency food parcels. They handed out 14,318 parcels in 2012/13. That rose to 71,428 in 2013/14. Just a couple of days ago a friend involved in children's charities told me she sees mothers visibly losing weight because they are going hungry to feed their children.

Families whose benefit payments have been cut can manage until someone needs a pair of shoes or there's a bigger than average bill to pay. Then they are sinking into debt.

In my lifetime I've never seen a time of greater need for state support. The economy may be on the up but it's not lifting everyone. To our shame, we live in an increasingly unequal society. If ever there was a moment to establish a zero tolerance policy for aggressive tax avoidance it is now.

I know some people don't see hiding their hard-earned cash from George Osborne's clutches as a serious offence. But failure to pay your fair and proper share puts an extra burden on decent people who pay up - those hard-working families again? - and damages our quality of life. Tax translates into public services.

It is wrong, a scandal. Mr Cameron should have said so.

In 2012 the Conservative MP Ben Gummer proposed sending a statement to each tax payer outlining what their money was spent on. He did a breakdown of the tax paid by an average earner. On a salary of £25,500, the tax take was £5979.

From that, the spend went as follows: £2080 pensions and benefits (including £212 on Housing benefit and £296 on Incapacity benefit.) The NHS received £1094, Education £824, Defence £339 and the Police £160. He itemised it down to £28 on the European Union.

I think the statement is an excellent idea. It brings home how valuable for society, for all of us, taxes are. And since not everyone can stay awake through the Chancellor's budget speeches, it would heighten awareness and benefit democracy.

Also it makes plain who suffers most when rich people avoid their responsibilities. It is not the government. It is the poor, the sick and our children. Is there any justification for man like Barlow to hang onto his OBE, even if he has demonstrated a commitment particularly to disadvantaged youth and has given his time repeatedly and willingly?

Is the Prime Minister right to cite his charitable work in mitigation?

The answer is no. Barlow is as venal as the MPs who were creative with their expenses.

I'd ask a further question and wonder why he received the honour in the first place. Do those who are already rich and famous need public recognition of this sort?

There are armies of unsung heroes and heroines dedicating themselves to charitable work in this country. They do it with no thought of personal gain or public glory which is just as well since most of them receive neither.

If a rich and influential man like Barlow uses his position to do as much that is, of course, admirable. But he will receive his reward in the increased admiration of his fan base. He will be feted by the great and the good. A trip to the palace and the recognition that brings is of course a filip. But think how much more it means to those for whom it is possibly their only glimpse of splendour; their only reward.

I hope Barlow returns his OBE with an abject apology. I also hope that he regularises his tax affairs and continues his charitable work.

And I hope he does so without the prospect of another honour. That would be another way of paying back.