In Sir Paul Smith’s office, you will find: a rubber chicken, a photo of David Bowie, a photo of Paul Smith with David Bowie; roughly 500 vintage cycling jerseys; countless books, on subjects that include Giacometti sculpture, British female artists from 1520 to 1920 and memorable Volkswagen adverts; a framed pair of swimming shorts signed by Martin Parr; a phone shaped like Snoopy; a set of Estonian dominoes; a giant Anglepoise lamp; lots of paintings; and a six-feet-tall pencil.

It’s a treasure trove, a minimalist’s nightmare and a slightly overwhelming peek behind the curtain of a great creative mind.

“People started sending me things,” Sir Paul says. “And they never really stopped.” He picks up a hand-painted stone that’s recently arrived from Utah, followed by a plastic goose that’s been sent from a mystery admirer, the address written directly onto its side. “The interesting thing about this room is that pretty much everything here is a gift from people around the world.

“Don’t think it’s childish,” he adds. “It’s childlike and full of playfulness, but it’s also full of innovation, things that surprise you and offer up fresh ideas. Why did somebody do that? What can I learn from this? I must get sent at least two or three things everyday… It’s extraordinary.”

In person, he is tall and trim, with dark glasses and a sweep of grey hair, weaving between rooms in a navy suit and a white shirt open at the neck. “I don’t own a hoodie or anything casual really,” he says. “I find suits more comfortable than anything else, they’re like a frame around a picture, drawing the eye in and holding everything in place.

“They’ve got pockets and room for a pencil, a notebook, your keys or wallet. The thing about our suits is that they’re designed to be comfortable, with a soft construction, a shallow armhole so you can move around. It’s convenient, and I do really like pockets.”

For our Essentials campaign, which highlights the classic pieces that comprise a well-rounded wardrobe, it made sense for Sir Paul to pick one of his iconic suits with a twist, in this case the Suit to Travel In. “This is a fabric that I developed quite a few years ago,” he says, pulling and stretching at a swatch of material. “A lot of people say that we’re famous for our colour and that is true, but that comes from accents, or touches. It’s mostly used in a subtle way.

“It’s all wool, and is naturally water repellent with a bit of stretch,” Sir Paul says. “It won’t crease, so you can wear it on a flight, or stick it in your suitcase and it will hold its shape and still look smart, which is fabulous.

“The word ‘essential’ is a good word,” Sir Paul says, settling into a low-slung leather chair at the head of the table. “What it means is, if you have a busy life, then having things that work together is very important. A black and blue suit, a white and pale-blue shirt, some classic shoes, a pair of sneakers, a nice sweatshirt or pair of chinos for the weekend.”

Sir Paul still loves all of it, even after all this time. The ideas, the collaboration, the pressure and the customers. On a Saturday afternoon, you can usually find him working the floor at one of his stores, a chance, as he puts it, to meet interesting people. He’s just back from a runway show in Milan. There are foundations and scholarships and only so many hours in the day. He’s curated a Picasso exhibition, which is travelling from China to Japan this year, where he also has more than 100 stores.

“You have to reinvent yourself,” Sir Paul says. “It’s important to never have too big an ego and realise that a lot of people are doing a lot of great things, so learn from them.”

It’s hard to think that, 25 years ago, the office we’re stood in – with high windows facing out towards a dreary London morning – was an empty box. Now it’s spilling over with colour, ideas, life and keepsakes from all over the world. People love the thought of him as much as they love the clothes. A boy from Nottingham who wanted to be a professional cyclist, who crashed his bike and opened a shop the size of a broom cupboard. A legend who made it happen again and again and again.

“Nobody cares how good you used to be,” Sir Paul says. “You’ve got to think about today, tomorrow, today, tomorrow.

“That’s all there is.”