The estate agent was waxing lyrical: “And across the river, ladies and gentlemen, rises the single tower of the iconic Battersea power station. As with the development of flats nearby we are about to visit,  a little imagination is needed to visualise all four rebuilt, but of course you are all property visionaries.”

A pessimistic estate agent is as common in Battersea as a zika-carrying mosquito, and about as popular, but the magnificent bull market in luxury London flats is ending at last. Around the power station they are whistling to stay cheerful, but the atmosphere is reminiscent of the last Canary Wharf boom. There, flats were bought off plan with 10 per cent deposits, essentially as a geared play on rising prices rather than as a place to live. Once the flats were built, real buyers proved hard to find, and prices plunged.

The evidence around Battersea, one of the largest residential developments in the capital, remains patchy. However, short sellers have hit Berkeley Homes, the impressively successful developer of unaffordable flats in London, while Steve Morgan at Redrow Homes blames the government (of course): “We abandoned looking for sites in central London…when the stamp duty changes came in. Those have killed high-end property.”

In practice, the market seems to be doing the killing without any help from George Osborne. There are 54,000 £1m-plus homes planned or under construction in the capital, for a sector which saw 3,900 sales in 2014. Since then the Russians have got nervous, Middle Eastern buyers are poorer and the Chinese face increasing capital controls.

The stamp duty changes pour sand into an already stuttering machine. They are also failing as a revenue-raising device, since the increase in transaction costs discourages owners of bigger properties from downsizing. The previous stamp duty regime was bad, but the changes demonstrate again that there is no situation so dire that government interference cannot make it worse. As for Battersea, we must hope the towers get rebuilt before the money runs out.

Dong! The bell tolls for cheap electricity

Gas prices are coming down, just in time for spring, but there is no corresponding fall in electricity bills. This is because so many costs have been dumped onto consumers that only 40 per cent of the bill is the actual cost of generation. This stealth tax follows legislation designed to conceal the true cost of wind farms, solar panels and biomass projects.

This is only the beginning. The promoters of the £1bn Swansea Bay lagoon are looking for terms which make the Hinkley nuclear power station seem cheap. They want a guaranteed £96.50 per megawatt hour – wholesale electricity currently costs £30-£40 – for 90 years. As a concession to sanity, they propose that the rate rises less fast than inflation, making it cheaper over time.

Still, almost anything is cheaper than Dong Energy’s £3bn Hornsea wind farm off the Yorkshire coast. We have guaranteed to pay an eye-watering £140 per megawatt hour when the wind blows, and to cheer us up Dong’s Brent Cheshire averred: ” If we are not cost-competitive by the mid-2020s, our business will be over.”

Dong also has a fifth of the unsubsidised £3.5bn Laggan Tormore gas plant, which started up this week and will provide 8 per cent of the UK’s energy whether or not the wind blows. The plant is uneconomic at today’s gas prices, but the capital is sunk, and consumers will get the benefit – at least until some new stealth tax arrives.

Bye bye buybacks

Rio Tinto’s management is among the best in a poorly run sector, but It has joined the others in demonstrating the stupidity of share buybacks. As recently as last December it paid nearly £19 a share  (it paid much, much more earlier in the year) to conclude a $2bn programme announced last February. A year on, and the “progressive” dividend is scrapped, replaced by a new policy which says, roughly, “we’ll make it up as we go along, but about half this year’s payout”. With the shares under £17, never has it been truer to describe buybacks as paying some shareholders to go away at the expense of those of us who remain.

This is my FT column from Saturday.