The sealant and compressed air can be injected through the tyre valve but the result achieved will depend on the cause of the puncture and how far and fast the flat tyre has been driven on.

In other words, tyre inflator kits only work on small punctures over short distances.  A major blow-out cannot be repaired using an inflator kit.  If you find yourself in a remote rural spot out of reach of a cell phone signal, you could be facing a long walk to get help.

Yet with automakers under pressure to produce more fuel-efficient cars, it is hardly surprising to see them eliminating the spare wheel, thereby shedding up to 30 pounds in one stroke. While some motorists may be surprised to discover their spare wheel is missing from the boot (trunk), automakers say it is not unsafe to go without.

Here in the UK, there is no specific legal requirement for automakers to include a spare wheel with a vehicle.  The only law regarding spare wheels is that, if a vehicle carries one and the driver resorts to using it, it must pass all the laws relating to a car's other tyres, such as tread depth, condition and use.

Motorists can still opt for a spare wheel.  For instance, the Ford Fiesta list price shows a spare wheel and tyre as an optional extra of £50 for all models.