ukfuel.live · Updated daily · Data: Fuel Finder UK / DESNZ
Today: Petrol 140.3p/litre · Diesel 148.2p/litre

Why Don't Petrol Prices Fall as Fast as They Rise?

When the oil price spikes, pump prices follow within 24-48 hours. When oil falls, pump prices drift down over weeks — if at all. This asymmetry has a name: the rocket and feather effect. It costs UK drivers billions of pounds every year.

Petrol today
140.3p
Diesel today
148.2p
Typical price rise lag
24-48h
Typical price fall lag
2-4 wks

What is the rocket and feather effect?

The term describes a well-documented pattern in retail fuel markets: prices rise like a rocket when wholesale costs increase, but fall like a feather when costs decrease. The same oil price movement produces a fast, sharp response at the pump in one direction, and a slow, sluggish response in the other.

This is not a conspiracy theory — it is a widely studied economic phenomenon documented by the Competition and Markets Authority (CMA), the RAC, and academic researchers across multiple countries. In the UK it has been consistently measured over decades.

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Why does it happen? The main causes

1. Inventory pricing

Forecourts buy fuel in batches at a fixed wholesale price. When that cost rises, they pass it on immediately. When the wholesale price falls, they continue selling existing inventory at the old (higher) margin — there is no incentive to cut prices until the cheaper stock arrives. This creates a natural lag on the way down.

2. Asymmetric risk management

Retailers face penalty for pricing below cost (regulatory scrutiny, margin collapse) but not for pricing above the market. This creates a systematic upward bias. When oil falls, retailers are cautious — what if it bounces back? When oil rises, there is no such caution.

3. Tacit coordination

The CMA's 2023 market study found evidence of tacit coordination among UK fuel retailers — not illegal price-fixing, but a rational pattern where firms follow price rises quickly (to avoid being undercut) but are slow to initiate price cuts (to avoid triggering a margin-destroying race to the bottom). The result is a market structure that systematically favours retailers over drivers.

4. The tax floor effect

With fuel duty fixed at 52.95p/litre and VAT at 20%, over 60% of the pump price is tax. This creates a price floor that limits how far prices can fall even if oil becomes very cheap. It also means that in proportional terms, a small oil price fall produces a proportionally smaller pump price reduction than the same oil price rise produces an increase.

What the CMA found in 2023

The Competition and Markets Authority published a major study of the UK road fuel market in 2023. Key findings:

How much is it costing you right now?

At the current petrol price of 140.3p/litre, economists estimate the rocket and feather effect adds roughly 2-5p per litre to what a fully competitive market would produce. That's approximately £1.75 on every 50-litre fill, or over £35 per year for a driver filling up fortnightly.

Is it getting better?

The introduction of mandatory price reporting under the government's Fuel Finder Scheme — which powers the live data on this site — was designed to increase transparency and reduce the effect. Early evidence from 2024 showed some improvement in supermarket margins. But the fundamental market structure that enables asymmetric pricing has not changed, and independent forecourts continue to show the classic rocket and feather pattern.

What can drivers do?

Track live petrol and diesel prices across all UK regions — see where prices are right now.

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