The chip maker ARM decided against listing its shares in London, despite plenty of arm twisting from the government. The building materials group CRH decided last month that New York was a better place for its equity to be traded, leaving the FTSE for good. The mining giant BHP has moved its listing from London to Sydney, while another materials group, Ferguson, switched from London to New York last year. And now hotel group IHG may make the same journey.

At these rates, no one will need the Prime Minister’s new plan to boost numeracy to count the number of companies still listed on the London market. The fingers of one hand will be more than enough to tot up the total. The direction of travel is a disaster. The London equity market is in a steep decline – and the government needs to take action, quickly.

It is madness to sit idly by and watch the London Stock Exchange dwindle into irrelevance. The LSE is too important for the City to allow that to happen

Keith Barr, the chief executive of IHG (which operates the Intercontinental and Holiday Inn chains), told the Financial Times last week that while there was no urgent need to switch its listing, that could well change in the future. If it did, it would be yet another blow for a stock market that has seen a whole series of exits over the past year. Company after company has decided that the London market does not have enough investors, taxes are too high, offices are too expensive, and the infrastructure too poor for it to be worth the bother of keeping their listing in the capital. They can do better elsewhere – and it is hard to blame them for reaching that conclusion.

This could still be turned around. The government should ditch the absurd layers of corporate governance regulation that have built up over the years and replace them with a simple requirement to publish audited statements. Whether the CEO had too much power, whether there were enough women on the board, whether it met sustainability or environmental targets or whether it was socially inclusive enough could just be left to the managers and the shareholders to work out between themselves. At a stroke, that would make London the simplest equity market to raise capital in. After that, the Treasury should relax the rules on pension funds and tweak the tax system to encourage investing in London listed shares again. Right now, only 6 per cent of UK pension fund money goes into shares quoted in this country. Get that up to 30 or 40 per cent and a huge amount of cash would be released.

It is madness to sit idly by and watch the London Stock Exchange dwindle into irrelevance. The LSE is too important for the City to allow that to happen, and the City is too important for the wider prosperity of the UK to be allowed to stagnate. Rishi Sunak and his Chancellor Jeremy Hunt need to move a lot faster. If they don’t act soon, the London market will be completely irrelevant – and it will be too late to do anything about it.