Among the political strands exposed by the Conservatives’ decision to pick Susan Hall to stand for London mayor – not least the apparent unlikeliness that she can win – is one that might seem niche but is in fact arguably very telling: what it says about active travel.

Anyone who has observed Hall in her six years as a London assembly member, and especially her energetic and often outspoken Twitter feed, will have realised she is not a fan of cycle lanes, cycling, or indeed of cyclists themselves.

While Hall intermittently insists she is not anti-cyclist as such, she has lambasted those on two wheels as lawless and dangerous, raised the idea of mandatory registration for cyclists, and claimed bike lanes and other active travel measures cause congestion.

There could be an argument that given the long odds on Hall unseating Labour’s Sadiq Khan next May, and the slightly arbitrary process through which she won the nomination, such opinions can be written off as marginal, even irrelevant.

This would be wrong. There are several ways in which Hall’s one-woman war against cycling, and her subsequent adoption as the governing party’s choice to inherit the biggest direct electoral mandate in the UK, is significant and telling.

First, her opinions are not too far from those now emanating from the Department for Transport (DfT), which has pointedly said it will no longer fund low-traffic neighbourhoods, a relatively routine intervention that seeks to make smaller residential streets more friendly to pedestrians and cyclists.

In an interview earlier this month, the transport secretary, Mark Harper, chose to criticise such schemes as tending to be about “banning cars or making it difficult for motorists”.

It is not a coincidence that Hall is a keen member of the Conservatives’ “culture war” faction, a section of the party whose views are often fanned by stories in a handful of rightwing newspapers, and that has an increasing influence on Rishi Sunak and his team.

Active travel – or, more specifically, moves to try to incentivise this over urban car use – has become increasingly drawn into this orbit, in part through traditional politics such as Conservative opposition to Khan’s expanded ultra-low emission zone (Ulez), but also, at the fringes, through conspiracy theories linking traffic schemes to supposed UN plots to imprison people in their homes.

Culture wars and negative media headlines are not the only reason why Harper’s DfT is so sceptical about active travel, a view insiders say Sunak firmly shares. Among Conservatives, Boris Johnson’s strongly pro-cycling view was always seen as an outlier.

But it is undeniable that when you are a Conservative minister and looking for policies to axe, those that are already the subject of regular condemnation in friendly newspapers, not to mention considerable social media froth, are an easy target.

All this brings us to the crux of why all this matters: on one of the more crucial policies for urban life in the coming decades, London and the UK risk not just falling behind but actively moving backwards, with potentially significant economic and social consequences.

For all sorts of reasons that would take too long to set out now, including the environment, public health, social equity, and the small matter of attracting businesses and tourists, cities around the world are trying to puzzle out how best to move away from cars and vans as the dominant transport mode for shorter urban trips.

Other places are moving fast. Paris is spending hundreds of millions of euros to make it more friendly for bikes and pedestrians, with dramatic and immediately visible results, while cities such as Brussels and Barcelona have also transformed their approach to urban streets.

Even Copenhagen, a city with a long record of high cyclist numbers, used its role as the departure point for the 2022 Tour de France to launch a heavily funded, multi-level push to try to get even more ordinary Danes on their bikes.

It is by no means universal, but in many cities, especially in Europe, this tide seems to be moving only one way. But Hall, Harper, and many other Conservatives, appear intent on trudging backwards.

Yes, many previous UK governments have paid little more than lip service to active travel, but they have generally praised it, at least in theory. Now we have a DfT that is at best neutral – and in Hall, a high-profile candidate who is actively hostile.

This is new, and in terms of other countries it is anomalous. And it matters.