Diesel Decline Watch: How Diesel Registrations and MOT Volumes Changed in May 2026
Diesel is no longer the headline fuel in new registrations, but it is still a huge part of the used market and the MOT system.
Based on AutoRank registration-date records and MOT tests completed in May 2026. Diesel MOT volume uses tests matched to diesel vehicles in AutoRank vehicle data.
Diesel registrations in 2026
March is the plate-change spike. May was almost level with April.
May registration share
30,198 of 185,550 May registrations were diesel.
The quick read
Diesel took 16.3% of May registrations in AutoRank data. That was almost unchanged from April at 16.4%.
The MOT side looks very different. Diesel vehicles made up 1,225,502 May MOT tests in the fuel-group view.
That is why diesel still matters. New-car demand is smaller, but the used diesel parc is still busy.
Diesel vans are still visible
The May diesel registration table still has plenty of working vehicles. Maxus Deliver 9 led the diesel model list, followed by Ford Transit and Peugeot Partner entries.
Ford Transit Custom, Mercedes-Benz Sprinter and Renault Trafic variants also appeared in the van-heavy slice.
MOT pass rate
Diesel vehicles passed 75.6% of May MOTs in the fuel-group view.
That was lower than petrol, hybrid and EV. Mileage is a big part of the story, with diesel median MOT mileage sitting close to 98,000 miles.
Top diesel model records in May
Registration records can include trim and drivetrain wording.