'Content is important in both, but for summer you are relying on different constructions, colour, and lighter-weight fabrics.'

Egg-shaped car coats, elegant slim-line suits with a sporty cagoule or blouson slipped on top, feature in his autumn debut. It has a sporty Pierre Cardin-style modernism, but there is a hint of retro early '60s vibe evident in the tautly fitted polo shirts tucked into trousers, and the white sweater and sleek black trousers combo, which, worn with black gloves, gives it a bit of Cary Grant Hollywood gloss.

Colour and fabric are the designer's starting points, and he has used a manly palette of navy, charcoal, ebony and khaki with royal blue and emerald highlights and copper-coloured zips in the collection. The Zegna group is renowned for the fabrics that it produces in-house and these tweeds, lambs-wool and mohair cloths are as luxurious and polished, interspersed with leather and techno fabrics.

Z Zegna was launched in New York in 2006, and is younger in spirit than the tailored Ermenegildo Zegna label. 'It is connected, but it's not so much for the Ermenegildo Zegna connoisseur.

'It's for someone who is into fashion and likes to be associated with the quality and heritage of the brand, but isn't ready to step into his father's suit,' says Surridge. 'They are searching for a cooler element.'

Outwardly the look is chic and tailored, but the construction and feel of the garment is lighter and more performance driven with sports details, less pressing and an urban vibe.

Z Zegna expanded to Asia about five years ago, and in response to growing sales, Surridge made a whistle-stop tour around the region this year.

He says he was struck by how menswear is such a driving force compared to womenswear.

Surridge has worked with Prada, Burberry and, until a year ago, was head of menswear at Jil Sander.

He once toyed with the idea of becoming an architect, but the reality of sitting behind a vertical table with a ruler didn't appeal to him.

So instead, he trained as a womenswear designer at London's Central St Martins, where he was a contemporary of Phoebe Philo, the creative director of Celine and Stella McCartney. There wasn't a degree in menswear when he graduated in 1997, but he had spent a year working at Prada with Neil Barrett as an intern. That changed his life.

'There is a discipline to menswear that I really liked. It seemed more ordered and had a certain serenity compared to womenswear.'

Surridge was recruited by Calvin Klein in 1998 and moved to New York. Five years later, he went to work for Christopher Bailey on the Burberry London line for men, designing tailoring and outerwear. In 2007 he moved to Italy to work with Raf Simons at Jil Sander.

'That was great - working with such a celebrated visionary, and someone who had originally made his name in menswear,' he says of the designer, who has since moved to Christian Dior. 'Raf deserves it,' adds Surridge.

He is fluent in Italian, having lived in Milan for over four years, and describes it as a relaxing city.

'In London, it takes you an hour to just get out of your door, whereas in Milan you could almost be in the mountains in that time,' he says. 'It's in the centre of Europe, and you can get to France, Barcelona or Switzerland in an hour.'

He has the short compact build of a sportsman and enjoys skiing and running. That's just as well, as he confesses to having a sweet tooth.

'In Italy, with the pasta and cakes, it can be a little too much,' he admits. And being a talented baker doesn't help.

He is renowned for his cakes:

'I make a fruit cobble, which is everyone's favourite.' Now the designer finds he is on every guest list. 'They always invite me well in advance, so I have to make a cake,' he says, smiling ruefully.

Well, he knows what to do if he ever gives up the day job.