The carmaker has one of the youngest customer profiles in the business, with an average age of just 38, and the Leon SC is expected to resonate with the company's typical buyers.

‘Our DNA lends itself to a three-door,’ said brand director Neil Williamson. ‘We've not been able to offer one before. Now we can.’

Williamson believes the new model, dubbed the Leon SC, could go on to claim a quarter of all Leon sales – way ahead of the market average for three-door cars. Most will be captured from rival makes, says Williamson.

Like many brands, SEAT has seen strong sales in the booming UK market, in sharp contrast to the troubled conditions in Europe.

With 22,750 cars sold in the first half of this year, the company is on course to set a fifth successive sales record in Britain, its third-largest market. This is despite a range which covers only 52% of the market and which offers no SUVs or crossovers and no pure sports cars.

‘We've taken advantage of our opportunities when they have come along,’ said Williamson. ‘We are very strong in the retail sector where most of the growth is coming from, and the dealers are very focused on that. This year our growth is almost double that for the market as a whole.’

The tide of payment protection insurance compensation claims has helped the UK to buck the downward sales trend, he says, but is not the only factor. ‘To some people PPI has seemed like free money, although it's not been a huge driver. The main thing is that the economic indicators in the UK – house prices, unemployment levels, GDP and interest rates – are starting to look better. Consumer confidence and business confidence are moving up quite nicely.’

The SC is shorter and lower than the five-door Leon and features totally different styling from the front windscreen pillars backwards, giving it something of the look of a coupe. There are three trim levels – S, SE and the lower and sportier FR – priced from £15,370, which is £300 less than the corresponding five-door.

The five initial engines – 1.2- and 1.8-litre petrol turbos and 1.6 and 2.0-litre turbodiesels – will in time be joined by a 1.4 unit that shuts down two cylinders when cruising to save petrol, and a 1.6 diesel said to offer ultra-low emissions and ultra-high fuel economy.