Where UK fuel prices stand right now
According to PetrolPrices.co.uk's weekly index, the average UK unleaded petrol price on 29 June 2026 was 151.02p per litre and average diesel was 167.12p per litre. That is a meaningful fall from the year's peak — petrol hit 158.73p in May when the conflict in Iran pushed Brent crude sharply higher — but it remains elevated compared to late 2025.
The RAC confirmed that the government's planned September 2026 fuel duty rise was cancelled in May, with the 5p-per-litre cut extended to 31 December 2026. Full Fact and the GOV.UK fuel duty publication confirm that the legislative default from 1 January 2027 would add approximately 3p per litre in duty — worth around 3.6p at the pump after VAT, adding roughly £2 to a typical fill.
The relief is temporary. PetrolPrices.co.uk notes the "cliff edge" has moved from September to January — not disappeared. Drivers who rely on their cars daily should be planning ahead.
The hidden fuel cost: your own car
Most drivers focus on the pump price. Fewer consider that the car they are filling up may be consuming significantly more fuel than it should — because of maintenance items that are overdue or unknown faults that have not yet triggered a warning light.
Here are the key mechanical culprits that directly harm fuel economy:
| Item | Typical fuel economy impact | How to fix it |
|---|---|---|
| Dirty/clogged air filter | Up to 10% worse MPG | Replaced at every full service |
| Worn or fouled spark plugs (petrol) | 4–8% worse MPG | Replaced at manufacturer intervals, typically 30,000–60,000 miles |
| Wrong or degraded engine oil | Up to 5% worse MPG | Oil and filter change at every service |
| Underinflated tyres | 2–4% worse MPG per 5 PSI low | Check monthly; correct pressure in your door jamb label |
| Faulty oxygen sensor / lambda sensor | Up to 40% worse MPG if failed | Engine management warning light — diagnosed via OBD |
| Dirty fuel injectors | 3–8% worse MPG | Injector clean or replacement as needed |
Figures based on US EPA and UK motoring industry data. Actual impact varies by vehicle model and conditions.
A car that is 10–15% less efficient than it should be costs a driver covering the UK average of 7,200 miles per year an extra £180–£270 per year at current pump prices. Over three years without a service, that is the cost of the service itself — wasted at the pump.
What to check now — before duty rises in January
With the next fuel duty increase pencilled in for 1 January 2027, the second half of 2026 is a logical window to get your car in its best mechanical shape. A full service from Motor Medics addresses every item on the fuel economy list above — fresh oil, air filter, spark plugs (where applicable), tyre pressure check, and a full diagnostic scan for any stored fault codes affecting fuelling or ignition systems.
- If your last service was more than 12 months or 10,000 miles ago — book a full service.
- If you have an engine management light showing — book a diagnostic before it costs more.
- If your tyres look low or you cannot remember the last time they were checked — we check pressures as standard on every visit.
Motor Medics comes to your home or workplace across Coventry, Kenilworth, Leamington Spa, Warwick, Bedworth, and Fillongley. No garage drop-off, no waiting room, no lost half-day. View our servicing prices or book online today.
Frequently asked questions
- When is fuel duty going up in the UK?
- The September 2026 rise was cancelled. The 5p fuel duty cut now runs to 31 December 2026. The next planned increase is 1 January 2027, adding approximately 3.6p per litre at the pump (including VAT). Final rates will be confirmed at Budget 2026.
- What is the current petrol price in the UK?
- As of 29 June 2026, average unleaded petrol is 151.02p per litre and diesel is 167.12p per litre, according to PetrolPrices.co.uk.
- How much can a poorly maintained car waste in fuel?
- A clogged air filter alone can reduce fuel economy by up to 10%. Combined with worn spark plugs, low tyre pressure, and degraded engine oil, total overconsumption can easily reach 15–20% of your fuel bill.
Local Service Areas: We provide expert vehicle servicing, diagnostics, and repairs for drivers across the West Midlands. Whether you need a garage in Coventry, Solihull, Kenilworth, Berkswell, Meriden, or Balsall Common, our workshop is easily accessible.
