AMID all the Brexit uncertainty, not much is predictable.

However, it would be remiss not to acknowledge that at least a few things are as reliable as clockwork in the post-Leave vote world.

This fact was underlined this week, with Prime Minister Theresa May waxing lyrical about the potential for the UK to benefit from increased trade with the Commonwealth. It was inevitable, as the UK Government flounders around and Brexit draws nearer, that she would seize the opportunity presented by the 2018 Commonwealth Heads of Government Meeting being held in London to make this sales pitch.

It is a most tiresomely familiar refrain, but seemingly also a real favourite fairy tale of the Conservative Cabinet. This fantastical refrain is repeated ad nauseam even as some Brexiters try to continue to claim exiting the European Union is not about harking back to days of Empire and throw their toys out of the pram when anyone dares to state this is what it is about.

The problem is that Conservative ministers believe the idea of a Commonwealth-related export bonanza is grounded in reality.

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Back in the real world, the evidence of the actual effects of Brexit, as opposed to the imagined and still utterly elusive benefits, continues to mount.

The International Monetary Fund’s latest forecasts this week put the UK near the bottom of the pile among the major advanced economies in terms of projected growth rates for 2018 and 2019, way adrift of the US, Germany, France and Spain, although ahead of Italy.

The IMF highlighted again its expectations that business investment in the UK would “remain weak in light of heightened uncertainty about post-Brexit arrangements”.

UK Government ministers have made much of high-profile glad-handing trips to Commonwealth countries since the June 2016 Leave vote. International Trade Secretary Liam Fox, for one, seems to be pinning a lot of his hopes on the Commonwealth.

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However, nothing of substance has materialised from these trips. Fine words butter no parsnips, as the saying goes.

The Commonwealth, beyond the Games and a bit of pomp and circumstance of the type we are seeing this week, is not really that much of a thing in the modern world.

In contrast, the EU is a very big thing indeed when it comes to future prosperity of the population at large.

One paragraph in a story by Reuters on Mrs May’s Commonwealth trade push summed up the situation well: “The Commonwealth, headed by Queen Elizabeth, is not a formal trading bloc with a free-trade agreement. In 2015 it accounted for only 9% of British exports while by contrast the EU, which Britain voted to leave in 2016, accounted for around 44%.”

Whenever Mrs May and her Government try to big up the potential from exporting more to Commonwealth countries, it is crucial to remember just how much more important the EU is when it comes to the UK’s international trade.

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These vastly different proportions of UK exports going to other EU countries and the Commonwealth were highlighted in an article published by the Office for National Statistics last year, which observed: “The Commonwealth makes up a relatively small part of UK trade.”

The ONS noted in last year’s article that UK goods exports to the Commonwealth totalled £25.1bn in 2015. In the same year, UK goods exports to other EU countries were worth £134bn.

It has also been disheartening this week to hear former prime minister David Cameron reveal he does not regret calling the referendum on EU membership in the first place, even though he wishes the result had gone the other way. He tried to claim the decision to hold a referendum was not entirely political but was rather about giving people a say.

However, in essence, nothing he said provided any new material to explain why on earth there had to be a referendum.

His lack of regret is perhaps also interesting. It would be easier not to regret the decision, it could be argued, if you are not one of the millions of households in the UK to have seen their financial woes, arising in many cases from years of Conservative austerity misery, exacerbated by the Brexit vote.

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The Leave vote sent the pound tumbling and inflation surging, as well as dampening business investment and reducing further what was already extremely unimpressive UK growth.

The IMF notes the “United Kingdom is an exception to the pattern of below-target inflation” in advanced economies.

Business economist and former Bank of England Monetary Policy Committee member Andrew Sentance put it rather well yesterday on Twitter when he declared: “David Cameron may not regret the Referendum, but about half the electorate does. A disastrous act of national self-harm, which has already led to the UK slipping from 5th to 7th in the global economic league. And we haven’t left the EU yet!”

A rare chink of light this week on the Brexit front came from an embarrassing defeat in the House of Lords for the Conservative Government on the EU Withdrawal Bill in relation to its sheer bloody-minded determination to leave the customs union, regardless of the consequences.

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Peers on Wednesday night defeated the Government on the thorny issue of staying in a UK-EU customs union after Brexit. Lords voted by 348 to 225 in favour of a plan requiring ministers to report on steps to negotiate a continued union.

Backing the plan, former European Commissioner Lord Patten declared the UK would be worse off unless current arrangements continued.

There are myriad reasons for regret over the Brexit vote, whatever Mr Cameron might tell you.

None of the reasons have anything to do with internal Conservative Party struggles or the type of high-brow but esoteric debates that might be heard in the elite tier of private schools in the UK or at some universities. Most of the reasons relate to the reduced living standards of, and curtailment of opportunities for, millions of people.

And, if the best the UK Government can come up with so long after the Brexit vote is to bang on about the Commonwealth, there are also myriad reasons to worry deeply about the future.