Three out of four second-hand tyres inspected by trading standards FAILED road safety tests.
The warning came after London Trading Standards (LTS) teams visit 150 businesses as part of a tyre safety project.
Operation GRIP took place from January to June, and aimed to raise motorists’ awareness when buying second-hand tyres.
During the project, officers visited businesses and offered guidance on how to store, mark and assess used tyres legally.
Undercover inspectors bought 51 used tyres across London and measured them against the legal road safety limit.
A whopping 74 per cent of tyres checked by Trading Standards and safety charity TyreSafe failed to meet safety standards.
LTS warned that 33 per cent of tyres inspected showed serious safety failures, while a further 41 percent had marking issues.
The legal limit for minimum depth of tyre tread is 1.6 millimetres.
Gerry Hearne, chair of LTS’ Product Safety Group, said: “The results of our used tyre checks carried out with Tyresafe are concerning.
“The numbers indicate that there are serious safety flaws with a significant proportion of the used tyres on sale in London.
“Consumers need to be aware that part worn tyres which don’t comply with the law pose significant safety risks, as explained in TyreSafe guidance.
“Should members of the public suspect that used tyres they have been sold do not meet legal requirements, they should report the trader to Trading Standards via the Citizens Advice Consumer helpline.”
London Trading Standards is a coordinated partnership of 33 local authority trading standards services across London.
They share intelligence and work collaboratively to ensure services can maintain consumer protection ‘despite severe cuts’.
Stuart Jackson, TyreSafe chairman, said: “Our investigations with Trading Standards across the country universally reveal an appallingly high level of illegal practises among retailers of part worn tyres.
“That’s of grave concern as tyres are a safety critical product – if they’re not in roadworthy condition, a vehicle’s brakes and steering are compromised.
“Londoners should be concerned that three-quarters of tyres in this investigation failed to meet legal safety standards – TyreSafe’s advice is always buy new whenever possible.”
Trading standards play an important role in product safety, and have ‘exclusive powers’ to remove unsafe products from the market.