How can big companies keep the sparks of innovation alive?

Innovation is a big buzzword in business, and much of the advice given can be good for start-ups and others news to business.

But what about the bigger companies who have been around for years, or even decades?

How do they stay ahead of the game and continue providing products and services which are true to their brand but also ahead of the competition?

Some top CEOs talk about the challenges facing businesses.