Alex Wild is Research Director at the TaxPayers’ Alliance.

Since 2010, Conservative-led Treasuries have introduced at least five new taxes and changed plenty of rates and thresholds. Despite this, one thing has remained remarkably consistent: the tax take, as a percentage of GDP. In 2010-11 it was 33.6 per cent, this year it is going to come it at 33.9 per cent.

There have been significant increases to the personal allowance and an eight-year fuel duty freeze which have reduced the Exchequer’s reliance on both of these cash cows. Income tax now accounts for 26 per cent of tax receipts, down from 29 per cent in 2010-11 and fuel duty now accounts for four per cent of tax revenues, 15 less than it did in 2010-11. Reliance on VAT, stamp duty and capital gains tax has increased markedly, however.

It’s usually been the case that under Conservative governments the tax mix has shifted away from direct taxes towards indirect taxes, while the reverse has generally been true under Labour governments.

It’s very difficult to get a sense of what George Osborne wanted to do with the tax system. He complained about complexity while in Opposition, but his tenure as Chancellor saw huge complication of the tax system. And if recent reports are to be believed, Phillip Hammond isn’t going to announce any tax changes at his Spring statement.

The lack of strategic direction is worrying and, given the tight parliamentary schedule and arithmetic, it seems that reform will have to wait for the next chancellor.

Much public discourse revolves around who (invariably the rich) should pay how much tax, but the question of what to tax is more fundamentally important.

This question poses a far greater political challenge. Hard Left populists like John McDonnell don’t care about incentives, distortions and how the tax system affects the functioning of the economy in general. To them, the tax system is simply a tool of class warfare. Higher rates for “the rich” and “the corporations”, no matter the consequences. It is as easy a sell as it is a bad idea.

The tax system shouldn’t tax companies at all. Incorporation certificates cannot bear the economic burden of business taxes, and it’s dishonest to pretend otherwise.

When it comes to Corporation Tax, the burden has to fall on shareholders, employees or customers, and while we do have some idea of where the burden currently falls, we can’t be sure. But even if we know that the lion’s share falls on employees, we don’t know which employees.

So when the likes of Corbyn and McDonnell call for Corporation Tax increases, they don’t even know who they’re proposing should pay more.

In Estonia, profits are only taxed when they are distributed, not if they are reinvested. And companies can fully expense the full cost of capital investment in the year in which it is made. Investment is the long-term source of growth and the absolute last thing the tax system should target.

While reforms along these lines would not be as radical as those proposed in the 2020 Tax Commission, in this area, and indeed many others, we could do a lot worse than copying the Estonians.

We do, however, know who pays employers’ National Insurance: it’s another tax on labour and it means a combination of lower wages and higher unemployment.

Indeed, the continued existence of National Insurance is very difficult to justify. For the majority of working-age people, it is another income tax with employer and employee components. The different assessment periods (weekly vs annual), assessment units (per-job vs per person), earnings definitions (all income vs employment income), and much more, make for a needlessly complex and opaque system with significant administrative costs. All these charges should be merged into a single income tax with transitional arrangements to ensure pensioners are not made worse off.

These changes would make for a simpler, more honest and transparent tax system.

Perhaps the worst thing Osborne did to the tax system was significantly increase Stamp Duty, although to his credit he did improve the system by abolishing the “slab rate” which saw £1 price differences result in vastly different tax bills.

Stamp duties, just like all transaction taxes, impede the effective allocation of capital. By taxing property transactions, Stamp Duty makes it more expensive for people to move. As a result, some will not take up higher-paying jobs in other parts of the country.

A revaluation of Council Tax bands, which are currently based on property values more than a quarter of a century ago, is well overdue. The addition of higher bands for higher value properties would be an acceptable price to pay if Stamp Duty could be severely reduced or abolished altogether.

Likewise, Capital Gains Tax creates “lock-in”. Especially when the rates frequently change, as they have in the past few years, it leads to people holding on to assets which could be better transferred to other owners.

Calls for wealth taxes have grown louder lately, but a future government should not be tempted down this path. The argument goes that some people, especially London homeowners, have seen the value of their properties soar and that this is in some way unfair and undeserved.

But taxes on assets which are hard to move are retrospective. People should not be taxed on decisions they have already made and just because someone lives in a valuable house doesn’t mean they have lots of cash with which to pay a wealth tax.

Taxes on assets that are easy to move or sell can easily be avoided, either by shifting to different assets or moving the assets abroad.

Any chancellor considering a wealth tax could do a lot worse than look back at the last serious attempts to introduce on in Britain in the 1970s. The then-chancellor Denis Healey gave up, saying that he “found it impossible to draft one which would yield enough revenue to be worth the administrative cost and political hassle.”

The UK is a major outlier amongst developed countries when it comes to fiscal centralisation. Around a quarter of public spending is at the local level, but only about five per cent of tax is collected locally. There is a plethora of empirical evidence that devolution leads to better value for money.

The impending move to allow local authorities to retain 100 per cent of business rates is a welcome move, but some form of local sales tax or local income tax should be considered. There are obviously reasons for this highly centralised system, not least concerns over what the “loony-left” councils of the 1980s would do. But it’s important to have trial and error and accountability in local government.

A lot of tax revenue is needed to finance a state the size of the UK’s, but all too often the wrong things are taxed, especially transactions. Tax revenue should principally come from income and consumption, not investment and “business”.

None of these decisions are politically easy. The Opposition will howl against reforms and frame them as giveaways to the rich, but they will say that regardless.

But reducing or removing the most economically damaging and distortionary taxes will mean more growth. And good economics is good politics, at least in the long run.