Which are the oldest cars on sale in the UK today? It's a question that’s not quite as easy to answer as you might think.

That's because there are an awful lot of models that have been wearing the same name for decades, the Mini, Porsche 911, Land Rover Defender and Caterham Seven among them. 

So I’m going to get a bit arbitrary here, and eliminate various models for being too different from their first editions to count. Dropping the Mini is easy, because it’s philosophically so different from the 1959 original.

The same goes for the VW Beetle. The Range Rover and Porsche 911 come closer to qualifying because the look and intent of both models is the same as it was when they were born.

But there isn’t a curve or component on either car that’s the same as it was when each of these was new, despite both being instantly recognisable. So they’re out.

The Land Rover Defender has changed substantially over the decades too, but it’s visually, conceptually and philosophically close to the original, and the pick-up version even shares a component with the 1948 version.

But the Defender is definitely not the oldest new car on sale today. That accolade belongs to the Morgan 4/4, which was born in 1936. Although many parts of this car have also changed, not least the drivetrain, the whole point of this car is that it is much the same as the 1936 original.

Tantalisingly, the 4/4 has only 22 years to go before it becomes the first car to have remained in production for a century. The 4/4’s Plus four sibling is a little less creaky for being launched as recently as 1938, while the positively youthful Morgan Plus 8 made its debut only 48 years ago in 1968.

Other oldies? There’s the Lotus Elise, which despite its facelift is the much same car underneath, making it 18 years old. It’s ancestor the Caterham Seven dates back to 1973 in brand terms, but the model itself, the Lotus Seven, was born in 1957.

Surprisingly, the conceptually similar Ariel Atom is now a decade behind, and the soon-to-be replaced Mazda MX-5 isn’t far behind at nine. And at the other end of the scale the Bugatti Veyron is ten.

Like sports cars, the four-wheel drive market is a haven for the wrinkling. The Mercedes G-class is now in its 35th year, the Suzuki Jimny has had its 16th anniversary, the about-to-be-replaced Volvo XC90 is 11 and the Mitsubishi Shogun is eight. Which is one year less than the Aston Martin V8 Vantage, whose exquisite styling hides its nine years well. 

Also scoring double-digit lives are the Rolls-Royce Phantom and the VW Caravelle. But toughening regulations and the imperative to renew have cleared many of the once-perennial oldies during the first part of this century, the original Mini among them. 

So, here’s our table of age. And its tail includes a few mainstream models in urgent need of replacement:

Morgan 4/4 – launched 1936, age 78

Morgan Plus 4 – launched 1938, age 76

Land Rover Defender – launched 1948, age 66 

Lotus/Caterham Seven – launched 1957/73, age 57/41