You’re sitting in a boardroom overseas, with money to deploy and jobs to create. The chair opens a discussion on where to invest it. I want to hear your ideas, she says.

Once upon a time, were someone to have piped up with “what about Britain?” it might have enjoyed a relatively smooth passage onto the shortlist.

Now? The suggestion would likely provoke a ripple of laughter, a moment of light relief ahead of the chair moving the discussion onto more sensible candidates.

The British Chambers of Commerce recently warned that investment by UK companies was going to fall at the fastest pace for 10 years. In 2018, business investment fell in each of the four calendar quarters, representing the longest sustained run since the financial crisis.

That matters. Ask yourselves what the world’s most dynamic economies have in common, say the Asian tigers that the Brexiteers drool over? They invest, heavily. Ditto the world’s biggest and most powerful companies. You think Apple got to be where it is today by scrimping on the future?

Tariffs in the event of a no-deal Brexit Show all 15 1 /15 Tariffs in the event of a no-deal Brexit Tariffs in the event of a no-deal Brexit Pork There will be tariffs on pork in order to protect British farmers Getty Tariffs in the event of a no-deal Brexit Cheese There will be tariffs in place on some cheeses including €22.10/100kg of cheddar, €19.10/100kg of processed cheese and €18.60/100kg on some blue cheeses Getty Tariffs in the event of a no-deal Brexit Milk There will be no tariffs in place on milk Getty Tariffs in the event of a no-deal Brexit Car Parts There will be no tariffs on car parts imported from Europe PA Tariffs in the event of a no-deal Brexit Cars However finished cars will face tariffs of 10.6% Getty Tariffs in the event of a no-deal Brexit Alcoholic drinks There will be no tariffs on alcoholic drinks - except on some rums due to ingredients used in their distilling process Getty Tariffs in the event of a no-deal Brexit Beef There will be tariffs on beef in order to protect British farmers Getty Tariffs in the event of a no-deal Brexit Fish There will be no tariffs on many types of fish including cod, haddock, salmon and sea bass Getty Tariffs in the event of a no-deal Brexit Fruit and vegetables There will be no tariffs on almost all fruit and vegetables Getty Tariffs in the event of a no-deal Brexit Chocolate There will be no tariffs on chocolate or other cocoa products Getty Tariffs in the event of a no-deal Brexit Poultry There will be tariffs on poultry in order to protect British farmers Getty Tariffs in the event of a no-deal Brexit Ceramics There will be some tariffs in place on ceramis Getty Tariffs in the event of a no-deal Brexit Steel There will be no tariffs on steel Getty Tariffs in the event of a no-deal Brexit Coal There will be no tariffs on coal Getty Tariffs in the event of a no-deal Brexit Lamb/Mutton There will be tariffs on the meat of sheep in order to protect British farmers Getty

In the past, the UK has been able to count on overseas investors to pick up the slack. Bringing it in is something we’ve been rather good at. Now? Just put yourself in that boardroom.

I recently came across a former civil servant who said, with great regret, that if they were playing the role of adviser to our board they’d tell it to run a mile.

A Brexit delay is inevitable and it remains the case that no one’s really sure how it will all end. About the only thing that’s certain is that a prime minister who looks increasingly unhinged, “leading” a party that has come completely unhinged, will make a mess of things.

The message we’re sending out is that a once sensible sort of country has completely lost its marbles. No wonder companies are heading for the exit as fast they conceivably can.

Let’s be clear, a Brexit delay is necessary, and a long one would be better than a short one. It would at least give us all a rest from the cynical brinkmanship the prime minister has indulged in, which seems motivated by her vanity and desire for a “legacy” as much as what might possibly be in the best in interests of the country she nominally runs.

But let’s also be clear that it will prolong the uncertainty that bedevils our stuttering economy. The investment that Britain desperately needs will only continue to fall.

Some of what has gone will never come back. Our fictional board will find another country in which to put its money. If it works out well, it will invest further funds. Did someone once say we ought to invest in Britain? Oh dear me, that was a good joke!

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The best outcome for Britain at this point would be for the government to revoke Article 50 and offer the people a Final Say. It’s also the most democratic, not that that seems to count for anything with our masters in Westminster.

But let’s not kid ourselves, it would mean still more uncertainty, more money going into contingency planning and reserves rather than being put to work; more funds going elsewhere.

Ian McCafferty, who sat on the Bank of England’s Monetary Policy Committee for six years and is now a senior adviser to Oxford Economy, this morning warned that the economy will be sluggish until there is clarity. His points were well made.

Even if the UK were to vote for the best deal, which is the one we have at the moment, it will take a lot of work to restore its national reputation; the perception that this is, despite its warts, a good place to do business.

There are grownups in the civil service and government agencies who are ready and willing to make a start, although they could probably all do with a long holiday.