How UK Garages Were Caught Charging Five Times the Price for a £110 Repair

• An undercover mystery-shopping investigation sent the same simple sensor fault to ten UK garages and found some quoted almost five times the fair price of £110.
• Four of the ten garages tested recommended unrelated extra work, including brakes, spark plugs and air conditioning servicing, adding between £400 and £950 to the bill.
• A separate survey of 2,000 UK motorists found 52 percent suspect they have been overcharged for car maintenance in the past five years.

The Same Fault, Ten Garages, and a Price Gap That Should Not Exist

Car diagnostics company Carly sent an identical, clearly diagnosable sensor fault to ten independent UK garages as part of a mystery-shopping exercise published in March 2026. The fair price for the job, based on parts and standard labour rates, works out at around £110. Several garages quoted close to that figure. Others quoted nearly five times as much for exactly the same fix, with no extra parts and no additional labour to justify the gap.

The investigation did not stop at price. Four of the ten garages tested used the visit as an opportunity to recommend work that had nothing to do with the fault the car came in for, including brake replacements, spark plugs, air conditioning servicing and duplicate diagnostic checks. Combined, the unnecessary extras would have added between £400 and £950 to a bill that should have closed at £110.

Most Drivers Already Suspect This Is Happening

A survey of 2,000 UK motorists commissioned alongside the investigation found that 52 percent believe they have been overcharged for car maintenance at some point in the last five years. That figure lines up with the mystery-shop results: the suspicion is not paranoia, it reflects a maintenance market where a driver has almost no way to check whether a quote is fair before agreeing to it.

The imbalance exists because most drivers cannot diagnose their own car. A dashboard warning light or an odd noise sends most owners straight to a garage with no independent read on what the actual fault is or what it should cost to fix, which leaves the garage as the only source of information the customer has. Carly’s investigation exploited that same gap deliberately, sending in a car with a known, verified fault to see what each garage would say and charge without knowing they were being tested.

Who Is Responsible

The garages named in the investigation vary between franchised dealers and independent workshops, and the pattern of overcharging appeared at both. There is no single regulator that sets labour rates or approves quotes before work begins, unlike an MOT test where the fee is capped. The closest thing to oversight comes from The Motor Ombudsman’s Trading Standards-approved code, which participating garages sign up to voluntarily, and from consumer protection law that requires any additional work to be authorised by the customer before it is carried out.

That authorisation step is exactly where several of the tested garages fell down. Recommending extra work is not illegal on its own, but presenting it as necessary when it addresses a fault the car does not have crosses into misrepresentation, which Trading Standards can act on if a driver complains with evidence.

How to Avoid Being the Next Customer Overcharged

Ask for the specific fault code before agreeing to any work. Every diagnostic scan produces an OBD fault code, and that code can be looked up independently in under a minute to check what it actually means and roughly what a fair repair should cost. If a garage is reluctant to give you the code itself, rather than just a description, treat that as a signal to get a second quote.

Get a second quote for anything over roughly £200 before authorising work, particularly for jobs unrelated to the reason the car went in. A garage that suggests brake work during a visit booked for a warning light should show you the specific wear evidence, not just tell you the pads are getting low. Keep the old parts if a garage swaps something out, since a legitimate repair leaves physical proof and a reluctant garage is a garage with something to hide.

Check whether the garage is signed up to The Motor Ombudsman’s code before booking, since that gives access to a free, independent complaints process if a dispute over price or necessity arises later. Paying by credit card for any single item over £100 also gives Section 75 protection, which can help recover money if a repair turns out to have been unnecessary or the work was not carried out as described.

The Difference Between a Franchised Dealer and an Independent

Drivers often assume a franchised main dealer is automatically the safer choice over an independent garage, but the mystery-shopping results found overcharging and unnecessary upselling at both types of business. Franchised dealers carry higher fixed overheads, from showroom space to manufacturer training requirements, which shows up in higher standard labour rates even before any padding is added to a quote. Independents vary far more widely, since pricing depends entirely on the individual owner rather than a national rate card, which means a driver can find both the cheapest and the most expensive quote for the same job within a few miles of each other.

Online reviews only tell part of the story, because a garage can hold a strong star rating built on friendly service while still overcharging on parts and labour that most reviewers have no way to evaluate. The mystery-shop investigation deliberately tested garages with a mix of review scores and found no reliable correlation between customer ratings and how fairly a specific job was priced.

What the Law Actually Requires Before Extra Work Is Carried Out

Consumer protection law requires a garage to give a driver a written estimate before starting paid work, and to seek authorisation before carrying out any work beyond what was originally agreed. A verbal call partway through a job describing extra work as urgent, without a revised written estimate, falls short of what the law expects, even though it remains common practice at many garages.

Drivers have the right to ask for the estimate to include a breakdown of parts and labour separately, rather than a single combined figure, which makes it far easier to spot inflated labour time or marked-up parts prices. A garage that resists providing this breakdown is not committing an offence by refusing, but the reluctance itself is a useful signal about how the rest of the visit is likely to go.

Why This Keeps Happening Despite the Complaints

The Motor Ombudsman’s code is voluntary, which means a garage can simply choose not to join and face no consequence for staying outside it. Complaints to the Motor Ombudsman about used car and garage disputes rose 14 percent last year, but that figure only captures the drivers who both suspected a problem and took the time to escalate it formally, rather than the much larger group who paid an inflated bill without complaint because they had no way to prove the work was unnecessary.

Trading Standards enforcement is patchy across different council areas, with resources stretched across far more than motor trade complaints, and most drivers do not know that misrepresenting necessary work is something Trading Standards can investigate at all. The result is a market where the mystery-shopping method used by Carly, sending in a known, verified fault and comparing what comes back, remains one of the only ways to see the scale of overcharging clearly, because individual drivers rarely have the reference point needed to know they have been overcharged until an investigation like this one puts a number on it.

Sources:

• Motoring Research, Undercover investigation reveals rip-off garages for car repairs, 2026
• Bodyshop Magazine, Drivers overcharged for routine vehicle repairs, warns Carly, 2026
• The Motor Ombudsman