The cost of Brexit is now plain to see. Some may be willing to stomach it, but everyone should have a Final Say

If Brexit is a price worth paying for the (mostly illusory) benefits of “taking back control”, then it is important to know exactly what that price is.

The latest estimate is that it has cost, over a three-year period, some 2.9 per cent of GDP. Less abstractly, that means about £69bn less in output of goods and services than would have been the case had we voted to remain in the European Union. It amounts, rather neatly, to about £1,000 for every man, woman and child in the British population – even before Brexit has actually happened (if it ever happens).

The longer-term loss will pile up over the years and decades until the much-vaunted trade deals with America, China, India and others start to make up for the loss of sales in Europe.

Indeed, they may never compensate for what is about to be lost, given that free movement of people across the EU has done so much for the UK economy, particularly in public services. No free trade agreement allows for such a radical injection of much-needed labour.

Some may believe that the loss of income and lower employment is worth it in order to secure control of our borders, immigration, money (ie EU budget contributions) and end the jurisdiction of the European Court of Justice. Their voices have been loud and often strident.

For those who do not share that view, and who in any case cherish the security, peace, solidarity and cultural benefits the EU bestows upon its citizens, they will make their voices heard in the march for a Final Say on Saturday.

Now that the country knows what the terms of Brexit are likely to be – harsh, one way or another – and can see once again parliament failing to resolve the crisis, it seems, more than ever, clear that the only logical answer is to ask the people to determine their own future.

What was started by the people should be completed by the people. A general election will do many things, but it cannot answer the question of Europe, and may well return another hung parliament.

Even the most ardent of Brexiteers should concede that investment, in particular, has suffered since the outcome of the 2016 referendum, as companies worry about the UK cutting itself off from its largest market. This is about more than “Brexit uncertainty”. It is, in reality, about firms delaying and postponing investment plans – in new plants, machinery, software and training staff – until such time as the situation resolves itself. If it resolves itself in favour of remaining in the EU, or to remaining in the single market or customs union, or both, then the funding for new investment will be released, in large part.

If the Brexit uncertainty resolves itself into what the government is proposing – a mere free trade deal, a hard Brexit or even a no-deal Brexit – then the investment will be permanently lost, and the hit to national income and living standards correspondingly greater.

For a free trade deal amounts to no more than the avoidance of tariffs and quotas on British exports of goods to the EU. It is still incompatible with modern “just in time” manufacturing techniques, and will also mean that British-made goods and agricultural products will not necessarily be accepted in the single market tariff free without verifiably meeting EU standards and “rules of origin”.

For professional, financial and other services companies, British qualifications will no longer be automatically recognised in the EU; and neither will British rulebooks in areas such as financial services be automatically and for ever regarded as equivalent and accepted by the EU authorities. Without orders and work from Europe, British companies will fold and many jobs will be lost. It is a simple matter of cold economic logic.

So the stakes remain high, and are growing, as the risk of no-deal Brexit looms once again. Indeed that £69bn or so will be merely the first instalment in a long-run erosion of the productive capacity of the British economy. If investment is the hardest hit component of national income, then the eventual effects on UK productivity will be grim indeed.

Increases in productivity spring from the introduction of new, faster and more efficient software and machinery, from IT, AI, and from the new working practices that flow from them. The benefits are enjoyed by companies in higher profits and investment and by workers in shorter hours, easier workloads, higher pay or a combination of all those elements as output rises and costs fall. Only by guaranteeing a more productive economy can long-term growth in living standards be delivered.

Attempts by the government to make up for the loss of private sector investment with huge infrastructure programmes – such as rolling out high speed broadband to every home and overdue improvements to roads and rail – are laudable, but cannot sustainably make up for the lost capacity.

The collapse in investment and impact on national income also means sluggish growth in tax revenues, higher public spending on welfare and higher government borrowing than would otherwise be the case. This would in fact amount to about double the amounts mentioned on the famous red Brexit bus – but with no benefit at all to the NHS or any other public service. HM Treasury, more broadly, and looking to the future, suggests that Mr Johnson’s deal will make each Briton £2,250 a year worse off than under the softer Brexit deal negotiated by Theresa May.

Last week, one vocal Leave voter declared he did not care about dire economic predictions and would be happy to end up eating grass as long as Britain left the European Union. They are entitled to that view, sincerely held. There is no need to disparage or insult people who hold such opinions.

Equally, though, there are many people who would wish to be part of the wider European community whatever the economic costs or benefits may be. Europe is more secure, more able to wield influence and exercise power as a united unit than as a set of smaller powers.

The fact that the EU has delivered unprecedented economic progress among its member states, including the UK, and remains a prosperous and peaceful magnet for global inward investment – from which the UK disproportionately benefited – is merely one of the many advantages of being a part of one of the world’s “big four” economies, alongside China, the US and Japan. Britain, on every useful measure, has always been stronger in Europe.