Think today’s fall in the pound post-Dominic Raab’s resignation is bad? You wait until we actually leave the EU

A no-deal Brexit – the most likely kind of Brexit after the cabinet resignations – would make today’s bloodbath look like a party

You know that old adage about keeping money under the bed?

Well if you stashed some euros or dollars there from your last holiday, congratulations. You now look smart.

You’ll have made money, at least in sterling terms, from Dominic Raab stamping his little feet and quitting over a deal he negotiated. Or at least helped to negotiate. BTW, don’t you just love the way a man who gives every impression of not having a conscience feels able to talk about resigning “in good conscience”?

But back to money, and the way he’s made ours worth less. The pound, which had rallied in response to yesterday’s deal with the EU, reacted to Raab and co deserting it like someone who’s just eaten a plate full of undercooked chicken: it threw up all over the City’s trading floors.

The two cents or so that it lost against the dollar, and 1.6 cents against the euro, might not look like all that much, but on the currency markets those numbers represent a veritable earthquake.

Dealers treated the UK’s currency like the Duke brothers treated frozen, concentrated orange juice at the end of Eddie Murphy’s Trading Places. They screamed “sell, sell, sell” as sterling drowned in a sea of red.

Ladies and gentlemen, we are officially in the bargain basement. Except that the pound doesn’t look like a good buy from the sale rail because it could get quite a bit worse before it gets better.

Recall at this point how Tory Brexiteers, during the EU referendum campaign, kept banging on about how rich we were all going to get through “taking back control”. Sure doesn’t look like that now does it? One wonders how it would have gone had they been honest and told everyone they’d be getting a whole lot poorer. But honesty is a commodity in short supply where they sit.

Of course, not everyone’s going to get poorer. Those with money in the FTSE 100 had modest cause for cheer. It rose (a bit).

That might look counter intuitive, but what you have to remember is that its biggest guns make most of their money in currencies other than ours. If the pound falls, their earnings are worth correspondingly more to sterling investors.

Bigger companies make the FTSE, which is weighted by market value, move more.

BP, at number three in terms of value, is worth £131bn. M&S, which is in the eighties, is capitalised at just £4.9bn. Let’s say the retailer has a horrible Christmas (which is par for the course at M&S these days) and loses 20 per cent of its value. BP shares would need to gain just 1 per cent to make up the FTSE 100’s losses from that.

BP and Shell (the top dog) are oil companies, and oil is priced in dollars. HSBC (number two) is a global bank, with businesses all over the world. However, it reports its earnings in dollars (and pays its dividends in cents). Ditto drug makers GlaxoSmithKline and AstraZeneca.

The biggest FTSE 100 company that is actually focussed mostly on the UK is Lloyds Banking Group. It is valued at a more than respectable £41bn, but that doesn’t even get you into the top 10. PS Its shares lost 5 per cent courtesy of Raab’s resignation.

Anyhoo, investments in companies that make most of their money in dollars, or euros, or even yen, are nice to have when your own currency holds all the allure of a cockroach infestation.

You want a truer picture of what the world’s investors think of what’s been going on here? Look at the FTSE 250 of second tier stocks. Its constituents mostly make their money in sterling and their fortunes are, like those of Lloyds, closely linked to that of the UK economy. The 250 fell out of bed, losing more than 150 points.

That may be just the start of it.

Sterling’s collapse, and the turmoil it has provoked more generally, is bad news for all of us. The “good consciences” of Raab and his friends are being paid for with our money. Billions of pounds of our money.

We import much of what we need, including quite a lot of our food, vital drugs and medical equipment, and most of our consumer goods.

Importing things just got a whole lot more expensive. That means inflation and potentially interest rate rises to stop it, which is the last thing an economy in turmoil needs.

The ministers who have deserted Theresa May’s sinking ship are mostly wealthy. So are the people they’ll knock around with on the back benches. Boris Johnson gets more than £200,000 for penning his Daily Telegraph column. Jacob Rees-Mogg gets a thumping dividend every year from the fund manager he and his mates set up to invest in countries not named Britain.

Look in the parliament register of members’ financial interests and you’ll see they’re far from alone in supplementing the £77,000 and change we taxpayers give them for sitting in parliament and creating a big fat mess for us.

It’s a fair bet that most of them have investments in the FTSE 100, and in other safe havens, to keep the champers flowing while the rest of us are wondering how to pay the bills.

My former boss, the Conservative peer Lady Wheatcroft, was on point when she said that this “increasingly looks like a posh boys Brexit”. It does.

I’m pleased to say she supports a Final Say. So do I. It’s just about the only thing that can save us from the poor house. And no I’m not exaggerating when I say that, because the consequences of no deal – the only realistic alternative to holding another vote – will make today’s bloodbath look like a party.