Swinging a fully laden electric van around a training centre in Bishop’s Stortford feels easy, with instant acceleration that belies the racks of heavy equipment in the back. Perhaps too easy, as the sudden shriek of its proximity sensor suggests the Guardian was a whisker away from a bill for some new paintwork.

The van in question belongs to Openreach, BT’s fibre broadband subsidiary. It is one of 6,000 electric vans out of 23,400 in Britain’s second-largest commercial fleet – and a further 1,000 are expected to be added by March.

The shift away from polluting diesel engines to electric will play a crucial role in the UK’s efforts to cut carbon emissions from vans – which were last recorded at 18m tonnes or 12% of all transport emissions in 2023.

Yet while the transition is moving forward for some of the biggest fleets, on a UK-wide level electric van sales have lagged behind expectations. For the white van, it has not been so easy being green.

On the face of it, electric van sales are behind government sales targets, known as the zero-emission vehicle (ZEV) mandate – echoing the situation for car sales. In 2025, the headline target was for 16% of new vans sold in Great Britain to be electric. Manufacturers only managed 9.5%, while struggling with an overall van market that slumped by 10%, according to figures published this week. That has led to a battle between manufacturers and some of the biggest buyers over how quickly Britain should make the switch.

For some fleets it makes sense. Royal Mail has the UK’s biggest commercial fleet, with about 43,000 vehicles. Posties drive pretty much the same route every day, before bringing their vehicles to a depot overnight. This pattern – with predictable mileage and a base to recharge – makes it easy to choose a van with the right size of battery, saving costs.

As well as 8,000 mid-sized electric vans, in the last month the company has also started using micro-electric vehicles – essentially rugged golf carts – and heavy electric lorries. Together those could cover the entire parcel journey with zero direct emissions.

Cost savings are the driving force for those companies which have switched. European sole traders – the white-van man, or woman – would save about €14,000 (£12,200) over three years relative to a diesel equivalent, according to a 2024 study by the Centre for Economics and Business Research (which was commissioned by Ford, seller of many more diesel Transits than electric models).

Upfront costs are still markedly more expensive – an E-Transit Custom starts at £43,630, compared with £33,750 for the cheapest diesel. Most of the savings from going electric come from charging being more cost-effective than diesel. Large fleets are also in a strong position to negotiate steep discounts – large-scale fleet buyers can get as much as a quarter off the list price when committing to a big order.

However, charging is difficult for some drivers, particularly if they have to rely on public chargers. Openreach installs home chargers for employees where it can, and also has deals to use other companies’ connections when their depots are empty during the day. Bulk charging deals mean it can get cheaper rates at public chargers when engineers are out and about.

Sitting in the converted telephone exchange building in Bishop’s Stortford, Judy O’Keefe, director of fleet at Openreach, said she valued the reliability of electric vehicles, avoiding roadside rescues which can cost £500 a pop.

“They are way more reliable,” she said. “Breakdowns, being left on the side of the road at night, are significantly down. Long term, the EV is the right way to go in terms of maintenance and servicing alone.”

But range anxiety is perhaps the main reason people are holding back. O’Keefe said that some engineers have been concerned about not having enough charge, but looking at fleet data, “I can see that engineer’s data and say, it is enough”.

Nevertheless, there is still clearly some way to go to persuade the majority of buyers to consider a green van. Yet as with the ZEV mandate for cars, the missed headline targets are not quite what they seem. The mandate has “flexibilities” – handy loopholes that allow manufacturers to gain “credits” that allow them to sell more vehicles with petrol and diesel engines. They can earn credits by cutting the emissions of the petrol and diesel vehicles they sell (a strong incentive to sell more plug-in hybrids), and they can sell more electric vehicles in later years to catch up. To complicate matters further, manufacturers can swap credits between their cars and vans.

The thinktank New Automotive has estimated that the actual target for last year was not 16%, but closer to 9.35%. If the estimates are correct it would suggest manufacturers are on track to avoid costly fines if they fail to comply. However, Mikes Hawes, chief executive of the Society of Motor Manufacturers and Traders lobby group, disputes that, saying the numbers are “significantly adrift of ambition”.

Whatever the flexibilities, the headline targets do increase quickly. For 2026, the headline target is 24%, and it will reach 70% in 2030, before sales of petrol and diesel vans are banned in 2035.

The big van makers in the UK are Ford, Stellantis (owner of the Peugeot, Citroën, Fiat and Vauxhall brands, among others) and Volkswagen – although, as in the car market, Chinese rivals are ruffling feathers, with Maxus recording fast growth.

Stellantis is the only company that still makes vans in Britain, at a plant in Ellesmere Port, Cheshire. However, Stellantis also exemplifies the difficulties facing European van manufacturers: in April it closed a factory in Luton that previously made Vauxhall Vivaro vans. It partly blamed the mandate, although some industry experts believed that Stellantis had too much capacity across Europe to meet lower demand.

Eurig Druce, UK group managing director for Stellantis, said the company is “more than compliant” with the rules once flexibilities are accounted for, but the complexity of the regulatory calculation “almost makes running the business a game”.

“We are as an industry considerably short of where the mandate sets out,” he said. “The reality for the majority of manufacturers in the UK is they’re struggling to comply. The take-up has been slower than any of us would have liked.”

Druce argued that the government should remove a cap on the number of electric van grants each buyer can use, but also that it should “review the trajectory” of targets as soon as possible. Otherwise the UK would “put in danger the investment in manufacturing in this country”.

“The market is not willing to follow,” said Druce. “The consumers do not follow at the rate of the trajectory.”

However, some companies – including energy companies Ovo and SSE, as well as Openreach, have argued the opposite: they want electric vans as soon as possible. Abby Chicken, Openreach’s head of sustainability, said an end to the “government oscillations over the last five years” would be helpful. However, she added that “the business case looks good” for switching to electric – alongside the “moral imperative” to cut carbon emissions.

Dominic Phinn, head of transport at the Climate Group, which runs the EV100 campaign to get big fleets to switch, said that its members – which include Tesco, British Gas owner Centrica, Lloyds Banking Group, and Next – “can’t get enough” of electric vans.

“It feels like another attempt by the automotive sector to slow things down,” said Phinn. “They’ll all snap into line. We’ve seen this time and time again.”

Ben Nelmes, chief executive of New Automotive, said that van makers of all stripes are under pressure because there is too little demand to use all their factory capacity.

“Most van makers still are making less profit on their electric van sales than they are on their diesel van sales,” said Nelmes. “They are doing everything they can to boost their margins.”

The vans used for a few years by the big fleets will eventually hit the secondhand market, giving sole traders electric options. For those who actually drive the vans, there is little appetite to switch back once they have had a go.

“This is so much easier to drive,” said Jordane Roach, an Openreach engineer demonstrating how to wire up a broadband connection. “It’s so much better. I’d never go back to a diesel.”