At the car
Found it flat in Nuneaton? Leave it where it is.
A tyre found flat has usually been losing air for a while: a slow leak from a screw picked up near the Bermuda Park units, a valve that has perished, or a rim seal disturbed by a Stockingford speed cushion. Driving it round to a garage on Hinckley Road seems sensible. It is not: a short run on a flat squashes the sidewall and shreds the inside, which ruins a Nuneaton tyre that was still repairable.
Keep the car parked, then phone with its location and the sidewall size. On arrival the fitter reinflates if possible to find the leak, removes the tyre and looks inside. A clean tread puncture gets repaired; a failed valve is swapped; a liner already damaged from running flat means a replacement, quoted before it goes on. Either way you get the decision at the car, not a guess over the phone.
On run-flat tyres? They behave differently once deflated, so check the handbook's limits and read our page on run-flat tyres; we fit replacement run-flat tyres at the car in Nuneaton as well.
If the job turns out to be different, see broken tyre replacement, wheel balancing in Nuneaton or 24 hour tyre repair.