The average UK diesel price has reached a record 199.18p per litre, according to the RAC’s figures for 28 September 2026.
That narrowly exceeds the previous record of 199.09p set in June 2022. The RAC says diesel has risen by 56.8p per litre since 28 February, when its national average stood at 142.38p.
These are national averages, not the price at every forecourt. Individual businesses will pay different amounts depending on location, fuel-card agreements, bunkering, rebates and purchasing arrangements. Prices can also change quickly.
The practical response is therefore not to assume one headline figure applies to every vehicle. It is to measure the business’s actual exposure and control the parts of fuel use that management and drivers can influence.
1. Calculate the real monthly exposure
Begin with litres, not total spend. Total spend moves with workload as well as price, so it cannot show whether the fleet has become less efficient.
For each vehicle, record:
- Litres purchased
- Business miles travelled
- Fuel cost on a consistent net or gross basis
- Pence per mile
- Miles per gallon or litres per 100 miles
- Route type, load and use of auxiliary equipment where relevant
A simple price-impact calculation is:
Monthly litres × price increase per litre = additional monthly cost
Using the RAC’s 56.8p increase since 28 February, a business buying 2,000 litres a month faces an additional gross fuel cost of £1,136 at the same consumption. At 20,000 litres, the difference is £11,360.
Those examples are not forecasts. They simply show why even a modest improvement in control becomes commercially important when the unit price rises.
2. Separate fuel price from vehicle efficiency
Do not blame every increase in pence per mile on the driver or vehicle. Split the change into two parts:
- The price paid per litre
- The quantity used to complete comparable work
Benchmark similar vehicles performing similar duties. A pickup towing on rural routes should not be compared directly with an unloaded van covering steady motorway miles.
Investigate changes rather than using one rigid target. Higher consumption may reflect extra payload, traffic, weather, idling for powered equipment, a different route or a mechanical problem. The purpose of the data is to find causes, not create a league table that rewards unsafe driving or inaccurate reporting.
3. Tighten fuel purchasing and card control
Set clear rules covering approved sites, fuel grades, mileage entries, receipts and out-of-hours purchases. Match card transactions to the assigned vehicle and check unusual volume, repeated small transactions, premium-fuel purchases and fills that exceed the tank’s plausible capacity.
Shopping around can save money, but a long detour may use more fuel and paid time than it saves. Compare the full journey cost before changing the authorised network.
Fuel cards, receipts and defect information often begin in the working cab. Give drivers a simple place and process for recording them so paperwork does not disappear between shifts. Keep cards secure and never leave PINs with them.
Farm Packs focuses on protecting working-vehicle interiors, but cab protection is not a fuel-saving device. Fuel control still depends on accurate records, a roadworthy vehicle and appropriate driving.
4. Reduce avoidable consumption safely
The Driver and Vehicle Standards Agency advises van operators to plan routes and manage speed, and notes that motorway fuel use can rise substantially at 80mph compared with 70mph. Energy Saving Trust guidance similarly recommends smoother anticipation and avoiding unnecessary acceleration and braking.
Brief drivers to:
- Follow legal speed limits and use an appropriate speed for the conditions
- Leave enough space to anticipate traffic and slow progressively
- Avoid unnecessary idling where it is safe and appropriate to switch off
- Use the correct gear without labouring the engine
- Follow the manufacturer’s instructions for driving modes and diesel-particulate-filter regeneration
Do not use fuel targets to encourage coasting, missed breaks, speeding, harsh driving, unsafe engine switch-off or continued use of a defective vehicle. Safety and the Highway Code come first.
5. Treat maintenance as a fuel control
Under-inflated tyres increase rolling resistance and can raise consumption as well as damaging the tyre. Use the manufacturer’s specified pressures for the vehicle, load and tyre arrangement, and check them with suitable equipment when required.
Defect reports should capture abnormal fuel use alongside warning lights, leaks, power loss, unusual regeneration behaviour and changes in how the vehicle drives. A rise in consumption can have several causes, so arrange competent diagnosis rather than replacing parts by guesswork.
Keep servicing to the manufacturer’s schedule and use the specified fluids, filters and parts. Removing emissions equipment or delaying safety-critical maintenance is not a legitimate economy measure.
6. Remove unnecessary miles and weight
Review the work before trying to extract another fraction of a mile per gallon from the vehicle.
Combine compatible visits, reduce duplicated journeys and allocate the nearest suitable vehicle. Check whether parts, tools or stock are routinely carried without being needed. Remove unused roof equipment where appropriate, while keeping every essential safety, recovery and job item.
Right-sizing matters too. A large van may be necessary for payload or volume, but an oversized vehicle used mainly for light local work can increase cost. Any change must still account for payload, axle weights, towing limits, load security, crew and business continuity.
Monitor failed deliveries, emergency parts runs and repeated return visits. They are operational problems that also consume fuel.
7. Set commercial trigger points
Fuel volatility should feed into quotations, contracts and replacement decisions rather than remain only a transport-department problem.
Review:
- Quotes that assume an outdated fuel price
- Contracts with no mechanism for exceptional cost changes
- Minimum order or call-out charges
- Route and delivery frequency commitments
- Vehicle replacement and hire decisions
- The whole-life cost of electric or alternative-fuel vehicles on suitable duties
Do not rush into a new powertrain solely because diesel has reached a record. Model the real duty cycle, payload, range, charging or fuelling availability, downtime, finance, tax, maintenance and residual-value assumptions. A controlled trial is stronger evidence than a national headline.
Set a documented trigger-for example, a sustained change in actual pence per mile or monthly fuel cost-that prompts management review. State who owns the action and which decisions they can make.
Start with four weeks of evidence
Download the last four weeks of fuel-card and mileage data. Reconcile litres to vehicles, calculate pence per mile, identify the three largest unexplained changes and give each one an owner.
The record diesel price is outside an individual fleet’s control. Purchasing discipline, route design, vehicle condition, driver support and contract decisions are not. Those controls will remain useful even if pump prices begin to fall.
This article provides general information and does not replace vehicle-manufacturer instructions, competent maintenance advice, tax advice, contract advice or a fleet-specific risk assessment.
Sources
RAC: Price of diesel reaches record high - 28 September 2026
GOV.UK: Weekly road fuel prices - latest release 28 September 2026
DVSA: Running a fleet of vans - current guidance, accessed 28 September 2026
Energy Saving Trust: Efficient driving training and advice - current guidance, accessed 28 September 2026
