Ever since Theresa May’s clarion address of the UK’s housing shortage (and how many successive PMs have embarked on the same brave heave-ho?) countless comment pieces have addressed the real problem that drives the disjunction between supply and demand. Nimbyism. Complex, protracted planning permission. Developer land banking. Rich Chinese and Russians investing in unoccupied properties as three-dimensional bank accounts. Excessive protection of green belts. Second homeowners. Empty properties the state should confiscate. The catastrophic sell-off of social housing. A wilful confusion about what the word ‘affordable’ means.

Yet when two statistics are out of whack, it behoves us to look at them both. All the above dysfunctions regard supply. Which suggests there’s something awkward about looking instead at demand.

At a Radio 3 Free Thinking event last weekend, I all but came to blows with my panel’s ‘rational optimist’, who believes that continued human population growth will be both modest and benign. The moment I mentioned the inevitable pressures on Europe of mass migration, the poor gentleman exploded, as if I’d tripped the pin on one of those grenades cropping up on the dodgier streets of Sweden. Something about how we screwed up in Libya, and the needs of the NHS… Give the guy this, he did rouse righteous applause from the great and the good progressives who attend events at the Sage Gateshead in Newcastle.

But let’s look at this housing business. It took half a century for the UK population to rise from 50.3 million in 1950 to 59.1 million in 2000. During that period, the foreign-born population rose from 4.3 per cent to 8.8 per cent — so a measure of that increase was already accounted for by newcomers. After an inflow historically unprecedented for this country, this brief century alone has seen the UK population shoot up to 65.6 million (as of January 2017), 14 per cent of whom were foreign-born as of 2016. We’re now adding another half-million every year. According to the Office for National Statistics, the UK population is set to cross 70 million by 2029; Migration Watch places that watershed even sooner, in 2026. That’s only eight years from now. While demographic predictions are notoriously undependable, near-term projections tend to be more reliable.

Oxford demographer David Coleman estimates that 85 per cent of the UK’s population increase from 2000 to 2015 is explained by migrants and their children. All these new people have to live somewhere. The pressure on housing, among many other social provisions, is intensified by the fact that on average foreign-born mothers have more children (2.06 in 2016) than women born in Britain (only 1.75). Fertility among foreign-born mothers has certainly dropped. Yet the high proportion of incomers in their reproductive years means the absolute number of babies with foreign mothers continues to rise. Thus the ONS asserts that in England and Wales in 2016 a staggering 28.2 per cent of births were to foreign-born women, ‘the highest level on record’. In 1970, that figure was 12 per cent.

We’ve heard about Britain’s recent ‘mini-baby boom’, but its primary cause isn’t native-born women hitting up the NHS for IVF in their forties and having triplets. It’s not appreciably caused by immigrants from eastern Europe, either. As of 2011, mothers born in Poland averaged 2.1 children — while mothers born in Pakistan had 3.8, and mothers born in Somalia had 4.2. So even Brexit — assuming it actually happens, and actually curtails freedom of movement (ha! on both counts) — may not appreciably constrain foreign increase.

The housing crunch is further complicated by the fact that so many immigrants settle in the southeast, where residential shortages are keenest. The population of Greater London in 2017 was 8.8 million, a rise of 400,000 over the previous five years. Greater London housed only 7.1 million people in 1997, when Blair opened the gates to permanent visitors. That’s 1.7 million more residents in two decades — an increase of over a quarter, two-thirds of which occurred in only the last ten years.

As of 2016, only 45 per cent of the capital was white British. An astonishing 58.2 per cent of births in London were to foreign-born mothers. (In the northwest London borough of Brent, 76 per cent of births were to non-UK-born women.) While over a third of the babies born in England and Wales had at least one parent born outside the UK, in London that figure was 66.6 per cent: two-thirds.

Hey, I know all about the fact that immigrants to the UK take up space, because I am a UK immigrant. Both Americans, my husband and I occupy a three-bedroom Georgian house that has thus been removed from the stock available to the folks who were born here. Next door to us lives a large family of Nigerians with numerous other compatriots eternally coming and going, who may or may not be accounted for by officialdom.

Indeed, most immigration statistics are untrustworthy — because they’re too low. London Councils former chairman Merrick Cockell told the BBC back in 2008, ‘London’s population is growing at an even faster rate than these figures suggest because official data has failed to properly account for the complexities of migration and population churn.’ A Westminster City Council spokeswoman chimed in, ‘The statistics leave out a massive “hidden” population and mean that local authorities are constantly short-changed by government as they still provide vital services to these people but receive no government funding for them.’

With all immigration figures, round up. Government has a) no idea how to track people with every motivation to keep off the radar, and b) every motivation itself to underestimate an unpopular social phenomenon, with a range of adverse consequences, that it cannot seem to control.

Do I sound bigoted? People can be bigoted, but facts can’t be. The UK’s housing crisis rests hand-in-glove with mass immigration. Without a doubt, nimbyism, arcane planning permission rules, Russian oligarchs — all that — make the situation worse. But effectively, even if Theresa May improbably abracadabra’d 1.5 million additional homes into this country by 2022, as pledged in the Tory manifesto? They’d be built for foreigners like me.