I AM by no means alone among motoring journalists in bemoaning claimed fuel economy figures that come no where near the actual figure achieved on road tests.

With annoying regularity, the real world figure achieved is usually about 15 per cent lower than that claimed by the manufacturer.

Then a car comes along that actually exceeds expectations. The Seat Leon ST (Sports Tourer) matched to a 1.6-litre diesel engine is one such rare beast.

During a week of road testing in very mixed environments in York and surrounding rural environments the trip computer recorded 75.1mpg on the instrument panel - the best I had ever achieved and even better than the claimed figure of 74.3mpg for the car.

Now forgive my cynicism, but when I see claimed average mpg figures above 70mpg I tend to dismiss them out of hand, but the Leon ST proved me wrong on this occasion, while also demonstrating why it is proving a popular buy. In theory, you could travel for 800 miles before refuelling.

Another will be the low CO2 emissions which mean there's no road tax to pay.

Even more astonishing are the figures for the 1.6 TDI Ecomotive version, which returns 85.6 mpg and emits only 87 g/km in all three body styles (five-door, SC, ST), making it the most efficient Leon ever.

You can well imagine the fleet managers rubbing their chins.

The new Leon ST retains the dynamic design and sporty characteristics of the five-door and SC models, but adds exceptional practicality through a a 587-litre boot, that, with the rear seats folded flat, has a load capacity of 1,470 litres.

Alongside achieving a distinctly sporty look, exceptional efficiency was very high up the list of priorities in its development . The fuel-efficient TDI and TSI engines, with displacements ranging from 1.2 to 2.0 litres and output from 105 PS to 184 PS, all feature direct injection and turbocharging.

The impressive fuel economy figures are not only the result of efficient engines, but of systematic lightweight design. In the base version, the Leon ST weighs in at just 1,233 kg, making it a mere 45 kg heavier than the five-door Leon and the lightest estate in its class. Nevertheless, the ST offers a host of functional equipment details that significantly benefit everyday usability. The rear seat backrests are extremely easy to fold down from the luggage compartment, while the double floor makes the boot very easy to load and unload. The passenger-seat backrest can be folded over to accommodate especially long items.

The much applauded design language of the Leon range has been further accentuated for the ST. Here, too, sculpted lines along the sides deliver a thrilling interplay of light and shade. The estate also features the same sharp lines and precise edges that communicate energy and vitality. The rear end, extended by 27 cm, provides an indication of the generous load space, while the angled rear windscreen, gently rounded roofline and muscular shoulders all emphasise the dynamic driving pleasure. The Leon ST is 4.54 metres long.

The technical elegance of the Leon ST is further accentuated by the optional full-LED headlights in combination with LED rear lights.

The well-balanced chassis makes the Leon ST brilliantly dynamic to drive. The finely tuned steering rack provides excellent feedback, while the suspension smoothly masters all manner of road surface irregularities.

For FR versions, SEAT is offering a new Adaptive Chassis Control (DCC) system with three different driving modes that can be selected via the SEAT Drive Profile. DCC is an additional function to the SEAT Drive Profile system already standard with FR-specification Leon models, adjusting the damper settings depending on the mode that Drive Profile is switched to.

In “Sport” mode, the Leon ST is even more agile, while the estate is noticeably more comfortable in the “Comfort” setting of the DCC system, selectable within the Drive Profile’s “Eco” or “Individual” modes. The optional Dynamic Pack includes DCC and Progressive Steering, which reduces steering effort when parking, while at the same time improving handling with more direct steering characteristics on winding roads.

New to the driver assistance systems for the SEAT Leon is the Adaptive Cruise Control (ACC). The radar-based system maintains the specified speed and a pre-set distance, automatically accelerating and decelerating in flowing traffic. The speed can be set within a range from 19 mph to 99 mph. ACC works with manual transmissions and DSG alike.

When it comes to driver assistance and infotainment solutions, the new SEAT Leon ST is fully up-to-the-minute. Safety technology includes Multi-Collision Brake, Tiredness Recognition and Lane Assist, while the SEAT Easy Connect infotainment operating system is an intuitive way of controlling entertainment and communication. Easy Connect includes a standard colour touch-screen and full Bluetooth phone and music connectivity.

At a glance

Seat Leon ST SE 1.6 TDI

Price: £19,495

Engine: 1.6-litre diesel developing 105PS

Performance: 0 to 62mph in 11.1 seconds; top speed 119mph

Economy: 74.3mpg combined

Transmission: Five-speed manual

CO2 emissions: 99g/km