It was claimed by sources close to Mr Willis, who is Mr Grade's deputy, that he had decided it was time to emerge from the shadow of his boss to smash the "myth of Michael Grade" when he was interviewed for the post last week.
The source claimed Mr Willis showed a new ruthless side last Tuesday when he outlined his "Manifesto for Four" to the trio of directors charged with finding a new chief executive for Channel 4: the company's chairman, Sir Michael Bishop, the former Granada chief David Plowright and Dr Mary McAleese, professor of law at Queen's University, Belfast.
The panel was taken aback to be told that Mr Grade may have been a great front man for Channel 4, but had not attended a scheduling meeting for three years. Mr Willis, the son of Lord Willis, creator of Dixon of Dock Green, has been described as the unsung hero of Channel 4 by Channel 5's Chief Executive, David Elstein.
He enjoys wide respect in the television industry. But he must have been alarmed by press speculation at the weekend suggesting Michael Jackson, one of the BBC's top television executives, was emerging as the favourite to capture what he and many others have described as the best job in broadcasting.
The story emanated in an Evening Standard report allegedly originating from pro-Willis delegates in the channel's comedy and entertainment department In London, at Channel 4's headquarters, the broadcaster's press office did its best last night to dampen down spin-doctoring for different candidates.
A spokesman said: "We are all amazed by this nonsense frankly, not least those who attended the meeting in which John Willis is alleged to have launched his attack."
Mr Willis, who is 50, has had a quiet image in the television industry until now.
Those putting the case for Michael Jackson and John Willis say creative leadership is what is required and commercial acumen can be supplied by David Scott, who was promoted from director of finance to managing director of Channel 4 shortly before Michael Grade announced he was leaving.
Yet the possibility of privatisation will continue to haunt the station even - or perhaps especially - if Labour wins the general election on Thursday.
If the incoming government does decide to raise some revenue for the Treasury by selling off a television company, the Channel 4's board would almost certainly want a leading business figure to lead it into a cut- throat commercial future.Reuse content