What an advisory actually is
An MOT advisory is the tester's way of saying: this passed today, but it won't forever. Since the defect system changed in May 2018, a fault found at an MOT is graded dangerous or major (both fails), minor (a pass, with the defect recorded), or noted as an advisory: an item that isn't yet defective enough to fail but is wearing out or starting to deteriorate. Brake pads with plenty of use left but visibly wearing, tyres legal but getting close to the limit, the first bloom of corrosion on a spring: advisory territory.
Three things follow from that. There's no legal obligation to fix an advisory. Nobody re-checks it until the next MOT. And every advisory ever issued stays on the vehicle's public record permanently, which is what makes them so useful: run any reg through our free MOT check and you can read years of testers' margin notes about a car you've never seen.
The advisories worth worrying about
Advisories aren't created equal. These are the ones that predict real bills:
- Structural corrosion: anything mentioning corrosion on sills, subframes, chassis members, suspension mounting points or floor pans. Rust never improves, welding is expensive, and this is the advisory that most often graduates into a major fail, or an uneconomic repair, within a year or two.
- Corroded brake pipes: a safety item with an awkward, laborious replacement job. “Corroded but not excessively weakened” is a countdown, not a pass.
- Suspension wear: play in ball joints, deteriorating bushes, corroded springs. Individually cheap-ish, but they tend to arrive as a family, and they affect how the car brakes and steers in the meantime.
- Tyres “close to the legal limit” or wearing unevenly. The tyres themselves are a known cost (price a full set before negotiating), but uneven wear is the bigger tell: it points at alignment or suspension problems that will eat the new tyres too.
- Oil or fluid leaks: “slight oil leak” can be a £20 gasket or the first line of a gearbox rebuild. Treat it as a question to answer before buying, not after.
The ones you can (mostly) relax about
Plenty of advisories are routine wear on a car that's simply being used, and on an older car a short advisory list is normal, arguably healthier-looking than none at all. Worn wiper blades, slightly discoloured number plates, a non-excessive play here or a minor stone chip there: these are maintenance, not red flags. The same goes for one-off items that were plainly fixed, a “tyre worn close to limit” advisory followed the next year by silence usually means new tyres went on. Context does the work: a single benign advisory on a ten-year-old car is Tuesday; five advisories clustered around one corner of the car might be the ghost of a kerb strike or a poorly repaired knock.
Reading advisories over time
A single test tells you about a day; the history tells you about an owner. Reading the record from oldest to newest:
- A repeated advisory is an ignored advisory. “Brake pads wearing thin” three years running means nobody changed the pads, and invites the question of what else was skipped. An owner who fixes things between tests leaves a record of advisories that appear once and vanish.
- Advisories that escalate tell a story: corrosion noted as an advisory one year and a major fail the next is the normal life cycle of rust, and a preview of what this year's corrosion advisories will become.
- A suspiciously clean recent test after years of advisory lists deserves scepticism, especially right before a sale. Compare it with the previous years and cross-check the mileage record while you're there.
- Our guide to reading a full MOT history covers the rest of the record: failures, mileages and test gaps.
Using advisories when buying
For a buyer, the advisory list on the most recent test is close to a free pre-purchase inspection. Before viewing, price up every open advisory: tyres, pads, discs, bushes, a battery. That number is your negotiating position, backed by a government record rather than your opinion. At the viewing, check whether the advisories were actually fixed; a seller claiming “all sorted” should have invoices. And fold it into the wider picture, the car's tax and MOT status, its mileage trail and the full buying checklist, before you talk money. A car's dashboard can be made to say anything; its advisory history was written a year at a time by people with no stake in the sale.