Will the Uxbridge by-election prove a crossroads for net zero?

Rishi Sunak has been dropping heavy hints that he may follow his predecessor but three, David Cameron, and cut what the latter called “green crap” – in line with demands from those already sceptical about the costs the net zero transition will impose on drivers and homeowners. Meanwhile Keir Starmer is pressuring his Labour colleague and London mayor Sadiq Khan to “rethink” his ULEZ policy out of concern at the Conservative’s success in weaponising the policy.

ULEZ was a local issue but resonates more widely

Khan’s policy to expand London’s Ultra Low Emission Zone to outer boroughs is designed to tackle the capital’s toxic air – and another Johnson legacy, this time from his spell as London mayor, when in 2015 he announced the ULEZ for inner boroughs. As such ULEZ is not fundamentally a ‘net zero’ policy and indeed predates the term, being designed to improve air quality not reduce carbon emissions.

However its expansion into more car dependent and less obviously polluted outer suburbs threatens to hit those with older cars – usually less well-off and with fewer public transport alternatives – at a time when many are already feeling the pinch of the cost of living crisis. And while City Hall does offer a ULEZ scrappage scheme, central government has supplied less funding for it than it had similar schemes in other UK cities.

The timing has made last Thursday’s vote particularly inflammatory. By-elections are often the venue for a protest vote – and with the ULEZ charge due to come in in late August, enough of the voters in Uxbridge used their ballot to register their protest not against the national government but against London’s mayor for his regressive tax on their transport choices.

But the impact has been to give the politicians in both major parties a jolt that the wide consensus on the need to act on the environment, and in particular climate change, cannot be assumed simply to translate into public willingness to pay the price. Politicians who have competed to set ambitious far off targets have been forced to confront voter concern about upfront costs. The Climate Change Committee is right to point out that in the longer run cars and homes may be cheaper to run once the transition has taken place – but at a time when people worry about their day-to-day finances, the costs of getting there loom large.

Both parties need to learn ULEZ lessons

The painful truth for both parties is that setting ambitious targets is easy – taking the measures to deliver them is much harder. Above all, the ULEZ example has laid bare the difficulty of implementing policies that create visible, and vocal, ‘losers’ – especially during a cost of living crisis and when public finances are stretched. Simply labelling a new tax or cost ‘green’ does not guarantee public support.

In practice the net zero policies to which the government is committed – the ban on sales of new petrol and diesel cars by 2030, the ramping up of heat pumps and an eventual ban on new gas boilers – would look and feel very different to the overnight introduction of the ULEZ. For most people the switch will come with a new purchase of a replacement. But the ULEZ warning is to make sure that the necessary help to adjust is in place before the policy can become demonised by its opponents.

It is possible that the net zero target itself becomes a battleground in the next election. So far neither political leader is seeking to back away from that – though Sunak has shifted his language somewhat since Thursday, saying government’s actions should be "proportionate and pragmatic". The need for action on climate change still seems to resonate with the public, emphasised to them nightly by pictures of summer holiday destinations turned into heat induced infernos.

Politicians need to avoid net zero cakeism

There is another inter-party consensus which Uxbridge might help break – for the better. That is on setting heroic goals while refusing to spell out the costs of transition. Both sides are guilty of that. Labour for example remains committed to going even faster than the government on decarbonising energy supply – even though the government is already struggling to meet its own ‘easier’ targets. If Uxbridge administers a dose of realism, that would be welcome.

But even if all Thursday's result does is introduce doubts about the degree of commitment to change, that could raise the costs of transition. Stop-start policies spook the private investors, whose willingness to invest their cash will be critical to the green transition – and mean they demand a higher return to compensate for that policy risk. The UK is already struggling to compete with the sums on offer in the US and the EU, and uncertainty may make the UK a less attractive market for footloose manufacturers.

It is too easy for politicians to will the end without being prepared to carry through the means. They cannot have their net zero cake and eat it. The risk of Uxbridge is that that turns one of Johnson’s more positive influences on UK politics into another of his darker.