I last saw a willow tit on my farm about a year ago. I’m searching for them again this spring, listening for their ‘chair chair’ calls, but I am worried that they may be extinct here. They are dying out everywhere: down by 92 per cent nationwide in the 50 years from 1967. And the reason is not pesticides or climate change or agriculture or habitat loss. It’s blue tits.

Willow tits have never taken to visiting bird tables, but blue tits love them. So come the spring, hordes of peanut-fattened blue tits fan out across the countryside looking for nesting holes and – hey presto – they find the little hollows that willow tits have been laboriously excavating in rotten birch trees and, being more aggressive, steal them. Some pairs of willow tits have been forced to give up four successive nest holes in a season to blue tits. And many of those that do manage to breed then watch their chicks eaten by woodpeckers, whose numbers have quadrupled, also thanks to bird tables.

This government up till its death is bringing in bans – cars, vaping – and subsidies: help to buy, energy bills 

I learned this from Richard Broughton of the Centre for Ecology & Hydrology in Wallingford, who has published papers on the topic and argues passionately in favour of the willow tit on what I can surely (in this context) still call Twitter. Immediately I learned this, I stopped feeding birds in my garden and won’t do it next winter: but unless my neighbours follow suit it will be in vain.

It’s subsidies for blue tits that are killing the willow tit. Subsidies are killing the lapwing too: roadkill and waste keep crows alive through the winter, leaving them ready to eat the eggs of the peewits in April.

The concept of the subsidised predator was introduced by a study in California 20 years ago, when a sudden decline in desert tortoises in the Mojave desert was traced to the opening of a landfill site. The landfill subsidised the raven population, which boomed and the ravens ate the young tortoises. Ecologists are learning that subsidised predators and competitors are among the most underestimated threats to biodiversity everywhere.

This lesson applies in economics and business too. Subsidise the wind industry to produce inferior electricity but with priority access to the grid and people stop investing in gas-fired power stations, even though electricity from gas costs a third as much to make today as electricity from offshore wind – and has been cheaper all along except for a brief period after Russia invaded Ukraine. Wind is stealing gas’s nesting holes.

Subsidise electric vehicles and you destroy the market for petrol cars – only in this case, much of the public does not want the inconvenience of an electric car so the government is having to resort to banning the cars the public do want. This would be like me noticing that subsidised blue tits are killing off willow tits but not coal tits, so going out and shooting coal tits.

In the British nuclear industry, subsidies saddled us with inferior Magnox/advanced gas-cooled reactor technologies, and on-going costs of £3 billion a year, even today. It drove out pressurised water reactors for a generation. We would never be so crazy as to repeat that experiment. So this time we’re scrapping the British bit, subsidising instead the French EPR technology, which has already been rejected by most of the rest of the world, and driving out investment in alternative and better technologies.

Probably the most egregious example of picking losers is the policy brought in by the Labour government of giving away compact fluorescent light bulbs to reduce carbon emissions. CF bulbs need less electricity than incandescents, but they warm up slowly, cast a ghostly pallor and are toxic when broken, so once again the public were reluctant to buy them. In 2012 the government banned the rival incandescents – sorry, ‘phased them out’. Yet who uses CF bulbs now? Almost nobody, because a far better technology was waiting in the wings: LEDs, the introduction of which needed no subsidy but was delayed by the CF bulb diversion. Last year the government banned the very CF bulbs they had previously given away.

I once had a bizarre conversation with a left-wing philosophy professor who would not acknowledge that there might be a category of things that were neither subsidised nor forbidden. Surely those were the only two options? We were talking about genetic testing. Either it must be ‘provided’ (subsidised) or it must be banned, he argued. The past 14 years of Tory government have alas shown that he was much more influential than I was. This government right up till its death is bringing in bans – boilers, cars, vaping – and subsidies: help to buy, eat out to help out, the energy bill support scheme, all of which are available to the rich.

Subsidising one industry to destroy another is popular with politicians. Why? Because it rewards those who lobby for subsidies, who then in turn reward the politicians for enriching them. The bulb manufacturers made fortunes out the CF bulb fiasco, some of which found its way to good seats at Wimbledon and Twickenham no doubt.

Imagine if the government was in charge of ornithology:

SIR HUMPHREY: Minister, there is a Mr Blue Tit here to see you.

MR HACKER: How nice to see you, Mr Blue Tit. Thank you for your donation to party funds. Now what can I do for you?

BLUE TIT: It’s about the bird table support scheme.

MR HACKER: Oh yes, ‘Nuts out to help out’. We think it has been rather a success.

BLUE TIT: Well, I am afraid it needs to be more generous. Some of our members went hungry last winter and were unable to steal willow tits’ nest holes. As a result those evil denier willow tits excavated wood from some birch tree trunks, increasing carbon emissions.

MINISTER: We can’t have that. Humphrey, see that we increase the subsidy.

SIR HUMPHREY: Certainly, Minister. See you at the opera tomorrow, Mr Blue Tit.