SEAT’s best-selling car, the sporty five-door Leon family hatch, is set to become even more appealing with the news that it is to benefit from the addition to the range of a hi-tech 1.4-litre TSI petrol engine.

Providing an important expansion of the existing, extensive Leon engine line-up – which ranges from a 102 PS 1.6-litre petrol right through to a 240 PS 2.0-litre turbo – the TSI manages to pull off something of an engineering coup. Despite boasting fewer cubic centimetres than the 1.6 it is most closely allied to in the price list, it still manages to be markedly more potent, more frugal and more environmentally friendly.

It also manages to make the Leon significantly quicker in the 0-62 mph dash, with a time that drops from 11.7 seconds to just 9.8 seconds.

This impressive piece of engineering works its magic by wringing extra efficiencies out of the 1.4’s seemingly modest capacity. Direct injection fuelling and an ultra-efficient single turbocharger boasting a more capable water- rather than air-chilled intercooler enable the 1.4 TSI to deliver some truly impressive figures.

That power peak of 125 PS is on tap at an accessible 5,600 rpm, while the peak torque figure of 200 Nm is on offer across a particularly broad rev range: 1,750 rpm all the way up to 4,000 rpm, to be precise.

What these impressive statistics translate into on the road is an especially flexible drive, with a surprising turn of pace that belies the engine’s unassuming capacity. The 0-62 mph improvement speaks for itself while the top speed, at all of 122 mph, is hardly tame.

For some, though, it’s sure to be the economy and emissions improvements that will seal the deal.

A combined cycle figure of 44.1 mpg compares particularly favourably with the 1.6’s 37.2 mpg, while the all-important CO2 figure drops from 180 g/km to just 155 g/km – shifting the Leon from Vehicle Excise Duty Band E to Band D and thereby shrinking Road Tax from £170 to £145 a year.

Head of SEAT UK, Peter Wyhinny, said of the new engine offering: ‘The arrival of this cutting-edge engine in the SEAT Leon line-up is another clear sign of our determination to lead the field not only in terms of sporting style and excitement, but also engineering excellence.

‘Smaller capacity, flexible engines like our 1.4 TSI really do deliver the best of all worlds: more power and improved performance with enhanced economy and reduced emissions.’

The new SEAT Leon 1.4 TSI, offered in lively Reference Sport and luxurious Stylance trim, is available to order now priced from £13,755.