As you may have noticed, we’ve seen rather more wokery than greenery from the Green party since Zack Polanski took the helm. If you’re wondering why, a party policy document on transport, revealed by the Mail, might give you a clue. The party wants to reduce motorway and dual carriageway speed limits to 55 mph, impose Welsh-style 20 mph limits in towns and (according to some sources) slap on a default 40 mph elsewhere. The party would hike fuel taxes, make parking more difficult even outside one’s own home, and bring in a more demanding driving test including such things as knowledge of how a car works, and impose it on drivers every five years. Driving would explicitly be made a privilege and not a right.

The Greens may be proudly libertarian in matters like drugs and borders, but they have a nasty authoritarian streak

We can start with the easiest point: these are terrible ideas. The Greens may be proudly libertarian in matters like drugs and borders, but there is a nasty authoritarian streak in their talk of rights and privileges, as if UK drivers needed to be treated like wayward schoolboys, to be given treats if they behave well. Furthermore, limiting your right to park your own car outside your own house and demanding that every five years you bone up on how a car works for an expensive test looks like regulation for the sake of regulation.

The Green proposals are also enormously regressive for a party that wants to take over Labour’s mantle as the party of the working class. Parking restrictions and a rise in fuel duty won’t overly worry someone with off-street parking in town or a double garage in the country (or both). They will make life hell for the small tradesman with his bashed-up van, and for the just-about-managing in a terraced house who need the car to get to work, or to Tesco, in a part of town that would otherwise involve an hour’s journey and a change of buses (assuming they run on time). And that’s before we begin with the inflation. Someone will have to pay more for the artificially expensive diesel used by the plumber who comes to mend your boiler (sorry, service your broken-down heat-pump) and for the extra hours spent by delivery drivers in getting your weekly shop at walking pace to that branch of Tesco.

All this says a lot about the Greens. Until a few years ago, they were a bit like early patrician Labourites on the Sidney and Beatrice Webb model: a mix of starry-eyed youths with a mission, a few committed technocrats and intellectuals, and a base of earnest hipsters afflicted with middle-class guilt and an impulse to change the world. To these people – always worried about the mistakes ordinary voters might make without clear guidance from their betters – these policies will be sweet reasonableness that nobody could rationally oppose.

However, things have moved on. The Greens are now in the big league, not because of any massive change of view by electors, but as a result of being sucked into the power vacuum created by the incompetence of a sclerotic and inept Labour government. And here is their difficulty. The new voters they now have to attract are precisely the electors of the housing estates of Middle England, who will not be at all keen on a party that tells them they will have to ditch their convenient older cars for much more expensive electric models. And they will seriously resent being told that if they want to drive down a clear M1 at a sedate 55 mph this is a privilege they must earn by taking an expensive and at times pointless driving test every five years.

So far the Greens have avoided these problems owing to inertia. A little like the Scottish nationalists north of the border, they have successfully presented themselves to traditional leftist voters as Labour 2.0, albeit with an environmentalist tinge. This is what happened in Gorton earlier this year: a run-down constituency, a combination of tribal voting, and nostalgia for what Labour had been but no longer was, combined to propel Hannah Spencer into power.

But this won’t work much longer. The Greens are in a cleft stick. They can’t afford to ditch their anti-motorist and anti-convenience policies without alienating their original base and seeming increasingly pointless. But equally they can’t hide them forever by harping about their general commitment to progressiveness. As the true implications of a Green vote become apparent, the electorate, who are not stupid, will smell a rat. Surprisingly quickly, the commentariat may well start talking of the passing of peak Green. And rightly so.