When considering the cost of buying and running a new car, how quickly a model depreciates is often overlooked. Things like fuel economy, road tax and servicing costs are frequently analysed in detail, but if the vehicle loses many thousands of pounds in the first couple of years, depreciation becomes a key factor.

Here we look at the top 10 fastest-depreciating cars in the UK, based on data from What Car? The car magazine used its residual value data to work out which models depreciate fastest, based on yearly mileage of 12,000.

10. Infiniti Q50 3.5h Luxe - retained value 30.4%

Price £43,450

Target Price £43,425

30k/3yr residual value £13,225

Price drop £30,225

There's no denying the eye-catching looks of the Infiniti Q50 3.5h Luxe, but this unique set of wheels will lose around £30,000 in the first three years/30,000 miles - enough to buy two brand new Vauxhall Adams. Ouch.

9. BMW 4 Series Convertible 420d Sport Prof. Media - retained value 30.3%

Price £44,535

Target Price £40,414

30k/3yr residual value £13,475

Price drop £31,060

A superbly-equipped convertible with comfort front and center, the 4 Series also boasts an excellent infotainment system. Space in the cabin and the boot is a rather modest, but depreciation, at about £31,000 over three years, is most certainly not!

8. Hyundai i40 1.6 CRDi SE Nav - retained value 29.7%

Price £24,000

Target Price £22,201

30k/3yr residual value £7125

Price drop £16,875

The i40 is a jack of all trades and, arguably, a master of none. The boot is spacious and the standard equipment good, but the interior falls down on quality and it's a forgettable drive. And with a retained value of under 30%, prospective buyers might think twice before parting with their cash.

7. Jaguar XJ 3.0 V6 diesel Luxury LWB - retained value 28.7%

Price £65,400

Target Price £54,952

30k/3yr residual value £18,800

Price drop £46,600

This fun-to-drive luxury saloon delivers top handling and comes in a variety of engines. But rear passengers don’t get much headroom and the interior quality is a somewhat disappointing. When you discover it will lose £46,600 in the first three years, any focus on things like fuel economy pale in significance.

6. Peugeot 308 SW 1.5 BlueHDi 100 Active - retained value 28.1%

Price £21,895

Target Price £19,639

30k/3yr residual value £6150

Price drop £15,745

If you want great fuel economy, it doesn’t get much better than the 308. This estate also delivers plenty of space and a great interior. However, after three years it will only be worth about 28% of the original buying price.

5. Vauxhall Astra Sports Tourer 1.6 CDTi 136 Auto SRi - retained value 28%

Price £26,735

Target Price £21,473

30k/3yr residual value £7475

Price drop £19,260

The diesel variant of this Astra-based estate is popular among company vehicle buyers and offers plenty of space. However, in terms of practicality other vehicles in the class might be a better choice.

4. Maserati Quattroporte V6 Diesel - retained value 27.7%

Price £74,320

Target Price £52,000

30k/3yr residual value £20,575

Price drop £53,645

Quattroporte buyers may not be overly concerned with depreciation - not least because its unique styling sets it apart from most other saloons on the road. But when one realizes it could lose around £53,000 over the first three years, those luxurious Italian lines might not look quite as wonderful.

3. Fiat Tipo 1.6 Multijet DDCT Easy Plus - retained value 27.5%

Price £20,510

Target Price £19,510

30k/3yr residual value £5650

Price drop £14,860

Great standard kit and a low asking price were not enough to take on the Ford Focus and VW Golf with much success - largely because of Tipo’s so-so drive. In addition, it only holds on to 27.5% of its asking price.

2. Renault Zoe 65kW i Q90 40kWh Dynamique Plus - retained value 26.6%

Price £29,270

Target Price £27,056

30k/3yr residual value £7800

Price drop £21,420

With a range of up to 132 miles and low running costs, this easy-to-drive small electric car is an attractive choice for those looking to ditch fossil fuels. However, it only keeps 26.6% of its original value - notwithstanding the government's £3,500 zero-emission grant.

1. Fiat Doblo XL Combi 1.6 Multijet 120 SX - retained value 26.1%

Price £26,183