At the car
Beyond repair on the A40 and the car is needed now.
Replacement becomes unavoidable when a tyre is torn by metal on Western Avenue, shredded after running flat round the Hanger Lane gyratory, or punctured right at the shoulder. For a delivery driver based in Park Royal or a carer covering Uxbridge, losing the car for the day is not realistic, and many modern cars leave no room for a spare, only a sealant kit that will not close a split.
Send the complete size code, noting any run-flat or electric vehicle markings, so a matching tyre, where the size is available, goes into the van at Brent Cross before it sets out. The price is confirmed on that call. Parked where you are, the fitter mounts and balances the new one; the three others are then checked for depth, cuts and wear patterns, with an honest word if another is close to the end.
If the job turns out to be different, see burst tyre replacement on the A40, emergency mobile tyre fitting or puncture repair.