Marketing guru Sir Martin Sorrell

Sir Martin Sorrell, chief executive of global advertising group WPP, said the amount of corporation tax companies pay is "a question of judgement". Sir Martin suggested that coffee chain Starbucks chose to pay a £20m royalty to the UK taxman because "doing good is good business".

When the Harvard Business Review interviewed Sir Martin Sorrell, the chief executive officer of WPP group, it asked him what his favorite ad of all time was. The single ad that Sorrell can't forget is pretty big news considering that he's one of the most important people in advertising.

Sir Martin Sorrell's position at advertising company WPP has been thrown into doubt after investors warned they will push for his departure unless he takes a pay cut.

Sir Martin Sorrell's position at advertising company WPP has been thrown into doubt after investors warned they will push for his departure unless he takes a pay cut.

WPP plc (WPPGY) Q2 2011 Earnings Call August 24, 2011 9:00 am ET Executives Paul Richardson - Group Finance Director, Executive Director and Chairman of Corporate Responsibility Committee Martin Sorrell - Group Chief Executive Officer and Executive Director Analysts Daniel Salmon - BMO Capital Markets U.S. Michael Corty - Morningstar Inc. Peter Stabler - Wells Fargo Securities, LLC