Just 3 per cent of new cars sold in showrooms today come with a spare wheel as standard, new analysis has revealed.
With car makers instead eliminating full-size and space-saver spare wheels in favour of lighter and cheaper tyre repair kits, there is an increased change of motorists being stranded at the roadside if they get a puncture.
The RAC has reviewed 313 new cars on sale today - ranging from the smallest superminis to the largest 4X4s - and found that only eight (2.6 per cent) come factory-fitted with a back-up wheel in the boot.
The breakdown assistance provider says this is causing a 'dramatic' rise in the number of incidents where drivers need help in the event of an unrepairable flat tyre.
Its patrols went out to nearly 200,000 call-outs last year where drivers had a puncture and no spare wheel, up from 165,000 in 2018.
The motoring group said it is predominantly larger, heaver-duty vehicles that come with a spare wheel, meaning the vast majority of family-friendly cars won't have them as standard.
Many manufacturers have stopped including a spare wheel as standard to reduce the weight of their cars by up to 20kg.
This makes the vehicles more fuel efficient but also helps car makers to meet tougher emissions legislation.Tyre repair kits are also far cheaper to offer as standard equipment in cars, meaning manufacturers can save money on each model they sell by not offering it with a spare in the boot or under the chassis.
It means buyers will almost always have to pay extra to have the convenience of a spare wheel in the boot.
For instance, Ford's Puma - which is the best-selling car in Britain so far in 2023 - doesn't have a spare as standard. For customers to spec a 'mini space saver' on a new order, it costs an extra £200.
And while a full-size of space-saver spare provide a simple short-term solution for a puncture, repair kits are sometimes difficult to use and often frustrate drivers due to their limited capabilities.
Anything bar a small puncture, be it a sizeable whole or tear to the rubber, will be too big a task for these repair kits and see them fail.
And pumping the sealant solution into the tyre usually renders it unrepairable (read more about the limitations of puncture repair kits in the boxout at the bottom of this page).
The RAC said spare wheels are set to shift from an endangered species to the extinct list because of the arrival of electric vehicles (EVs).
In many cases, their large battery packs take up the space where a spare would traditionally be installed, meaning ergonomically there isn't room to have one.
The only car models identified as having a spare wheel as standard were the Fiat Tipo, Ford Focus (selected variants), Hyundai Sante Fe (PHEV), Land Rover Defender, Seat Ateca (selected variants), Suzuki Across, Volvo XC90 (not PHEV) and Toyota Land Cruiser.
RAC spokesman Rod Dennis said: 'Getting a puncture on a journey has to be one of the most irritating breakdowns for drivers, especially if it's as a result of hitting one of the plethora of potholes that currently characterise so many of our roads.
'In the past, a driver could have reached for the spare wheel in the boot but this new analysis shows that these are now pretty much a thing of the past, with a miniscule number of new cars sold in the UK coming with one as standard.
'It's understandable therefore that drivers are increasingly calling on us to help them out of a tight spot, and it's a trend we fully expect to continue as electric vehicles are even less likely to come with a spare.
'Fortunately, we're continuing to innovate to ensure our members get the best service possible should they breakdown as a result of a puncture, having just rolled out a four-stud version of our pioneering multi-fit spare wheel, that's carried by every single one of our patrols.
'In many cases, drivers ordering a new car can still buy a spare wheel - whether that's a full-size one or the more common lightweight space saver type - as an optional extra.
'This might turn out to be a wise investment if you are one of the many drivers who unfortunately suffers a puncture.'