CAROL FISHER, CEO, CENTRAL OFFICE OF INFORMATION
As a trained historian I often look at today's events and wonder how history will judge them 30 or 50 years hence. The man for me who is the outstanding leader of the 20th century is Nelson Mandela. He has all of the qualities a great leader should have.
He understood both tactics and strategy and was prepared to play a very long game to achieve his objectives. He understood that in negotiations you need the 'win, win' concept and left the whites with their dignity.
He embraced all parts of the population and made them united in their shared pride in being South African. I remember a white South African telling me of the tremendous shared feeling when Mr Mandela donned a national rugby shirt during the World Cup. He achieved memorability by just being himself. That a man could be such a key part of the contemporary world after so long locked away, that his spirit was never destroyed whatever the odds and that he remains, still, a hugely respected and massively popular man makes me wish I had met him. I hope his retirement is a long and happy one.
JAMES HANSON, CHAIRMAN EMERITUS, HANSON
Leadership is about making things happen. 'Anticipate and Initiate' is a sign I have on my desk. Anticipate others' needs, initiate action to meet those needs and you will always be ahead of the game.
I'd like to sing the praises of one of the legion of 'advisers' without whom no public business enterprise can succeed. My choice is Peter Meinertzhagen (above), the head of stockbrokers Hoare Govett. Whenever you needed 'something in the City', Peter would get it done and that's leadership.
A top stockbroker will learn all about you and your business and keep himself completely up-to-date in order to guide and advise you. I could always confide in Meinertzhagen, and his impartial advice would be based on my needs, not his. As with your banker, lawyer and accountant, it's time to give credit where it's due.
GREG DYKE, DIRECTOR-GENERAL, BBC
The person who influenced my views on leadership the most was not someone I worked with but a Harvard academic called John Kotter - back in 1989 when I was about to become chief executive of LWT, I spent three months on the Advanced Management Programme at the Harvard Business School and first encountered John Kotter. He was passionate about the difference between leaders and managers and was very clear that leadership mattered most. What I took from him was that successful leaders could be idiosyncratic, even eccentric so long as they knew how to communicate.
What his course gave me was the confidence to be myself and not to adopt the language and attributes of the professional managers and the accountants when I took on the top job in the company. His message was clear, 'Don't change what you are just because you are now running the show - be yourself and if that means being unconventional so be it.'
ALAN SUGAR, CHAIRMAN, AMSTRAD
I am going to combine Rupert Murdoch and Arnold Weinstock into Rupert Weinstock, a formidable businessman. Rupert is a long-term, visionary business leader prepared to invest to get what he wants for his company.
When denied ownership of US media interests because of his nationality, he took out American citizenship. What could be more simple for a truly international businessman? Confronted in the digital satellite race by new boys ONdigital, he upped the ante by giving away set-top boxes. Rupert knows when and how to apply the pressure.
The Weinstock end displayed a more cautious approach, where cash and a relentless attention to detail were paramount, resulting in the growth of a cash-rich, multi-interest international combine of tremendous strength and depth. Rupert Weinstock is my man.
JOHN MONKS, GENERAL SECRETARY, TUC
I naturally look first at union leaders and pick Ernest Bevin. Bevin built the Transport and General Union into Britain's largest union and ruled it with dynamism and skill. Additionally, he was one of the first to see that Keynesian economics could help conquer mass unemployment.
He became minister of labour in 1940 and was a massive figure in the wartime coalition government, mobilising more of the country's resources than his counterparts in Nazi Germany. In 1945, he took over as foreign secretary in the Atlee administration and was instrumental in founding NATO. Trade unionist and statesman - not always right, he was hostile to the forerunners of the EU - a mighty figure of 20th-century history.
CHARLES MUIRHEAD, FOUNDER/PRESIDENT, ORCHESTREAM
The pace of technological change, and the rate at which businesses are changing, requires leaders to have a particular aptitude for technology and an understanding of the internet. Steve Jobs at Apple has shown vision, and an understanding of organisations, strategic issues and how they relate to technology.
A lot of people in the market are aware of the opportunities, but with clever marketing, product design and technological innovation, and very close attention to detail, he achieved so much. It wouldn't have happened without his awareness, and it's been instrumental in Apple's resurgence.
He has a different approach to management - he's very much hands on, he doesn't just say that 'this is a business just like any other'. He goes much deeper than that. A good example is their latest idea to make virtual disc space available to Apple users on the internet. The championing and execution of ideas like this comes straight from the influence and insight of the CEO. It's a great example of leadership in the age we're in.