Design certainly has a cosmetic, aesthetic aim. It always aims at making things beautiful. But relevance is just as important. I often say, 'If it isn't ethical, it can't be beautiful. But if it isn't beautiful, it probably shouldn't be at all.'

Integrating breakthrough technology into everyday products is always a challenge; at the same time, this is exactly how design makes tech products easily adoptable in life.

I have been working with Hive, part of British Gas, on reinventing the thermostat. Now you can control your heating at the press of a button on your phone. As I say, design should permeate every part of society.

My mantra is: 'Good design accelerates the adoption of new ideas.'

Having one foot in design and the other in sustainable and social projects, I hear this question quite often: 'Why does the world need another chair?' My answer is that the world needs another chair/bicycle/car or any new product for that matter, like the world needs another book.

The notion of 'reduce and refine' is one I've pursued. I truly believe that by making things less complex, by finding innovative ways to make sustainability affordable, we can advance the notion that it is possible.