Our children used to have to wait until we died to get their hands on our assets, if any. Now it seems they can’t wait. They beadily eye our ridiculously overvalued homes and it is only with great restraint or great affection that they stop themselves telling us to sell immediately and hand over some capital. Surely you would be happier in something smaller, they suggest. Get out, grandma, is the message and often well before we are a grandmother.

It’s not that they are greedy. It’s that they are beginning to be desperate. Property prices have risen to such dizzying heights that most cannot hope to buy a first home without help.

The average home in England costs seven times the buyer’s earnings; as recently as 1998 it was about five times earnings, but by 2026 it will be 10 times, even if the government succeeds in its plans to promote more house building. Most young people will be unable to afford to buy their own homes at all.

This was the warning last week – if we needed a warning – of the National Housing and Planning Advice Unit, a new government think tank. At the same time the Council of Mortgage Lenders reported that nearly half of first-time buyers under 30 were getting help from their families.

That leaves the other half, of course – of first-time buyers whose families can’t help them and an increasing number of hardworking and capable young men and women who realise that they may never own their own homes.

That has been true for generations; countless people didn’t even dream of being property owners. What is different now is that the successful and well educated middle classes are feeling the frustration and powerlessness that used to be confined to the lower orders. This has always been socially divisive. With prosperity and higher expectations it has got worse and it is compounded by the way that house prices are inflated near the best schools. This is the beginning of a crisis.

Everybody knows why property is so expensive. There aren’t enough houses and flats. Everybody knows that the answer is to relax the Soviet-style planning restrictions and build lots more, fast. But many people, including some of the most powerful and vociferous, have resisted the explosion of building that is needed, both to provide housing and to bring down prices.

I have myself, if only mentally. The blue remembered hills of my childhood in Dorset have been disappearing; the empty valleys, deserted beaches and forgotten woods are now noisy and crowded and, to me, spoilt, although not for those who now enjoy them and never knew them as they were. None of it is my back yard, except in my mind, but I have always had great sympathy with nimbyism.

However, the time has come to accept that there will have to be a great deal of building in places like that, particularly in the south of England, and probably in your back yard. The inflated cost of housing is a terrible social evil and to do nothing about it would simply be wrong. We are short of about 800,000 homes in England alone, maybe more. With increasing immigration and rising birth rates that number will grow fast: 1m immigrants have arrived here in the past decade and about 223,000 new households are formed every year.

We will have to accept a lot of building on greenfield sites and green belts and it will have to be low rise and low density. People overwhelmingly hate flats and long for houses with gardens. We will have to accept the suburbanisation of whole swathes of the country. However, it may not be quite as bad as we imagine.

The person who forced me to change my mind is Dr Oliver Hartwich who, with Professor Alan Evans of Reading University, has written three housing pamphlets for the think tank Policy Exchange. They argue that our attitude to planning is distorted by some powerful myths.

One is the idea that building on brownfield sites is the answer. It sounds good but the problem is that there aren’t enough of them to make much of a dent in the problem. Only about 14% of the houses we need could be built on them, according to the Rogers report. Besides, they tend to be in the wrong places where people don’t want to live and work.

Another myth, according to Evans and Hartwich, is the argument that Britain is a small and overpopulated country with little green space left. I’ve always assumed this myself; for one thing, a satellite photograph of Europe by night shows that the south of England is hugely more ablaze with light than anywhere else in Europe.

However, Evans and Hartwich argue that only about 8% of land in Britain as a whole is urban, a much lower proportion than in the Netherlands, Belgium or west Germany. In England about three-quarters of the population live in cities of more than 20,000 inhabitants and use only 7.2% of the land. The assumption that the southeast is the most urban is wrong, too; the northeast is the most urbanised region, with 22% of the area under urban land as against 17% in the southeast. The southwest and East Anglia have a much smaller proportion – between 6% and 7%.

As for the disappearance of rustic vistas, the authors quote research claiming that the proportion of UK land used for agriculture – 78% – is the highest in the old (preenlargement) European Union bloc, which has an average of 64.2% – again, the opposite of what people generally think.

The idea that concreting over green fields is bad for the environment is something they also call a myth. They argue that towns with plenty of garden space are better for biodiversity than some farmland, where pests and birds and weeds are eliminated. Urban and suburban gardens are full of interesting and unthreatened species.

In other words, a massive boom in house building will not necessarily be quite as destructive as one might fear. However, even if it were, it would still be right to bite the bullet. As things stand, government planning controls are distorting the property market with disastrous social consequences. They are promoting inequality, resentment and nasty, crowded housing of the wrong kind. Even the most recalcitrant nimby must see how unjust and dangerous that is.

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