This morning the CBI is publishing a report calling for a radical overhaul of the UK's corporation tax system.

The proposals are extraordinary. They show contempt for all those who work for a living in this country and who pay tax on their earnings at rates of at least 20%, plus national insurance at 11%. The CBI wants companies to pay much, much less. 18% is their proposed corporation tax rate. They offer no compelling reason why this difference that represents an exceptional break with the prevailing situation where companies are, at least nominally, taxed at 30% (soon the be 28%) can be justified economically, socially or politically. They simply say that it is competitive to offer this rate, and, as was implied on the Today programme on Radio 4 this morning, that they'll leave if they don't get it.

The proposals show similar contempt for small business: the CBI call for the same rate for large and small business when, as my research has shown, large companies pay an average rate 7.5% less than the nominal rate imposed upon them. My own experience as an accountant and the anecdotal tales of the many accountants I talk to suggests small companies pay tax at effective rates higher than those nominally set for them. Despite this at no point does the CBI suggest why it is appropriate to subsidise large business in this way whilst creating an impediment for small business. Again, this reversal of policy, which has for decades seen the tax advantage being given to small business, is not justified by the CBI. Isn't it time that their small business membership demanded reasons for its policy of contempt towards them on this, the domicile debate and other issues of concern to them?

As for the claim that the proposal will raise money there are three points to make. The first is that no evidence has ever been found for a Laffer effect, but they assume that it exists. Second, the country with which the CBI seeks to compare the UK is Ireland. they claim that Ireland's 12.5% tax rate has been a success for them. Well, undoubtedly it has raised revenue, but let's be clear that's the result of first mover benefit, and the UK won;t have that, and second it's the consequence of blatantly stealing other country's tax revenues - as was the case with Microsoft, for example. The simple fact is, there's only room for one thief in town. This is also why the CBI's so called 'dynamic simulation' of future revenues will not work. Ireland cannot be replicated, but they assume it can be.

But most of all, and thirdly, the proposals the CBI makes are a simple licence to tax fiddle:

1 A corporation tax rate of 18 per cent means companies will have lower tax rates than any individual: people will be rushing to set up companies to hold their savings and investments to avoid tax. The poorest will lose: they don't have savings or investments. They pay tax on all their earnings. Without massive anti-avoidance measures built in this proposal is simply designed to make the tax system more regressive, increase the gap between the rich and the poor and to add to the increasing tax punishment meted out to those who work for a living instead of living on their investment earnings.

2 Given that we know that when corporate tax rates are at 30% companies are actually paying 22% it's reasonable to assume that when tax rates are 18% companies will really pay 10%? How can that be justified? And, of course, this too will lower the effective tax rate on the richest in society, who own these companies.

3 The call for tax to be calculated on the basis of existing company accounts sounds good and would remove much of the deferred tax problem, but you can imagine what will happen. Companies will write off all their equipment costs in a year or two to get maximum tax relief in the shortest time possible, and their tax advising auditors will let them do it. Result: massive tax savings, or a need for regulation of accounting policies on a statutory basis. That's called capital allowances by any other name. Do they really have no understanding as to why we have the laws we have?

4 They're actually calling for a 'no surprises' legislative and administrative process. What this really means is that they want to write the laws and for Parliament to approve them. No thank you, very much. We once fought a civil war to make sure an elite couldn't control taxation and parliament could, and a lot of us would like to keep it that way.

5 There call for a non-political, independent tax law commission is as naive. They say this should be based on the Law Commission, which I run by lawyers. Take it as read then that what they actually means is that they want a body run by the CBI and the accounting profession. Since when were they non-political? If we really want a proper process for reviewing tax legislation then we should give an appropriate budget to the Treasury select committee to do a proper job on this issue. They're the right people to do it. Those who wrote this report are entirely the wrong people to do it.

6 The call for proactive UK government action on all cross border tax issues is actually a request that when a company sets up a head office in a filing cabinet in a tax haven the government should give up the right to tax it. Do they think we're stupid?

7 The call for the adoption if an exemption system for non-UK source profits is as na?Øve. This means that when a subsidiary s set up in a tax haven with no tax paid nothing will ever be due when that money comes back to the UK. Right now Dave Hartnett of HMRC has expressed his concern about UK companies shifting their profits offshore by artificial abuse of intellectual property that they claim is based there. What the CBI is saying is that they want open licence to do this. It's a massive licence to shift money offshore and pay no tax that they want. Their call for reduced burdens on proving transfer prices falls into the same category. It's very hard to take nay of this seriously.

8 Just in case this does not go far enough they are calling for tax reliefs for investment to be given even when there are no taxable profits against which to offset them - so now we have the CBI calling for negative tax rates for companies.

In combination this is the most massive abuse of the UK tax system proposed for a long time. The logic within it is apparent. It is obvious that the CBI has adopted Leona Helmsley's maxim that 'only little people pay tax'. In doing so it shows blatant contempt for all those who work for companies in the UK and who will pay tax at rates much higher than the large companies on whose behalf the CBI is arguing. It's also showing massive contempt for small business in this country, who would if the CBI's proposals were adopted find itself paying tax at much higher rate than big business.

There's no doubt what would happen if this proposal were adopted. It is likely that the effective tax rate of many large UK companies would fall from 22% to about 10%. Since these companies pay most of the £45 billion or so corporation tax paid in the UK each year what the CBI is asking for is a cut in the tax bill of the biggest companies in the UK of at least £15 billion a year. There is no reason to think otherwise; as I note above the case of Ireland cannot be replicated.

There's one thing the Treasury need to do with this report, and that's bin it. I suspect they will.