Countryfile is my guilty secret. On a Sunday evening, when I want to sit back and not think too much, BBC1 offers me an hour of alternative reality. It offers a Britain that is beautiful yet real, hard-working yet leisured, a place without streets, housing estates or crowds, yet unmistakably British. Its star presenter, Adam Henson, does not lie in the grass contemplating the view with a piece of straw in his mouth. He works. But round him people are allowed to play.

This year, Countryfile broke through 8 million viewers, putting it in the same league as Downton Abbey and Strictly Come Dancing. The appeal of the programme to Britain’s overwhelmingly urban population is undeniable. But is it what Henson claimed this weekend, that Countryfile offers not only space, a skyline, less light pollution, livestock, hills and mountains but also a “rural idyll”, somehow a place apart?

Watching a child deliver a lamb is captivating and gruesome

I have no doubt why the show works for me. It portrays the countryside as beautiful, but it shows a harder edge. The beauty has been manufactured by humans over centuries. This continues to require hard work, often yielding clashes and controversy. The landscape is awash not only with farmers but with conservationists, walkers, cyclists, field-sports enthusiasts and birdwatchers. Henson is himself a one-man Archers.

I like that roughly half the items in each programme are devoted to how farmers make money, and half to how others enjoy the product of their labours. There is always a running tension between these two. Watching a child deliver a lamb is captivating and gruesome. An item on the subsidy scandal of anaerobic digestion pulls no punches. The upland “rewilding” lobby is given a fair crack of the whip, as are both sides in the beaver and badger debates.

Farmers look after the landscape, but they can do immense damage. They should be held to account. And not only farmers. Some years ago, the programme put David Cameron on the spot, eliciting from him a pledge to protect the countryside as if it were his “own family”. Since his chaotic planning reforms have done more harm to the countryside than any policy in recent times, I was glad to see the programme rerun that interview and review subsequent performance. If Cameron indeed treats his family like he treats the countryside, I fear for his family.

The programme has faults. Its down-market pace, the constant chopping and changing for fear of losing audience, is irritating. Farmers are treated too kindly, their complaints indulged and that dreaded word – subsidy – too little mentioned (especially to sheep farmers).

But the secret of the programme’s success, I am sure, is as a window on a Britain that most viewers have forgotten exists. Britons take more holidays abroad than any other big nation. If they travel at home, it is by train or motorway between urban settlements.

As a result, the political consensus holds that there is no constituency for the rural landscape. It holds that people resent farm subsidies and feel that food could be more cheaply imported; if people want homes, build over the countryside.

This view of public opinion is clearly misguided. In survey after survey, “the countryside” rates with the monarchy, the NHS and Shakespeare among the most admired features of the national personality. Countryfile shows that this admiration is not an abstraction. It is indeed escapist, but that of a desire for relief from the confines of the city. It is escapism with attitude.

The countryside is today being extensively reworked to suit the demands of townspeople – variously for leisure, open air and wildlife. It is not so much a place where a small minority of the population works. It is where a majority of townspeople enjoy themselves. The Peak District national park is the second most-visited in the world. The Lake District and the Pennines are the lungs of the north-west. The Chilterns and Downs confine London in its basin, a constraint but also a blessed relief. All this must be recognised by farmers.

Britain after the second world war was the inventor and master practitioner of “town and country planning”. Today, its guardianship of historic buildings is relatively successful. Its guardianship of the rural landscape is deplorable. Cameron has put green belts up for grabs. Rural settlements are no longer allowed to grow organically, but are besieged by estates. Distribution sheds proliferate amid a wilderness of wind turbines and agribusiness. Their siting is no longer planned and regulated. It is let rip.

Amid all this, Countryfile is a political warning. It suggests that the countryside carries clout, not from the farming lobby but from a new group – a wider British public introduced to its qualities of beauty and delight. This is the most political programme I know.