It's hard to imagine industryites as diverse as David Puttnam, TV chef Gordon Ramsay, helmer Stephen Frears and comic Russell Brand, plus leading lights from all three main British political parties, joining together to sing the praises of a broadcaster -- especially one as anti-establishment as Channel 4.

But that's what happened a week ago when all were featured in a film that opened an event that announced what Channel 4 wants to be in the digital age.

The Next on 4 initiative represented the culmination of months of soul searching by the web as it struggles to redefine its role in the fast-emerging digital landscape and makes a case for a public subsidy that it believes is essential for its long-term survival.

"Our task is to ensure Channel 4 remains capable of connecting the largest possible audience with the public value we create, in an age when digital technology is shaking the foundations of mass media," declared station chairman Luke Johnson, an outspoken entrepreneur who has made a fortune from pizzas, bars and dental surgeries.

A year ago the web was in deep crisis, rocked by the bruising spat over racism in "Celebrity Big Brother," fraudulent phone quizzes that led to a $3 million fine from regulator Ofcom and critics lining up to say that the 25-year-old web had lost its way.

At the Next on 4 event Johnson, CEO Andy Duncan and director of television Kevin Lygo, who at times have been uneasy bedfellows, each spoke. They outlined their case for why the broadcaster still offered something unique in an increasingly crowded media market -- and why the government should give it a financial crutch of some $300 million a year from 2012, when the U.K. completes digital switchover.

Channel 4, owned by the state but funded by advertising, announced initiatives designed to help restore and boost its public service credentials. In future less money will be spent on U.S. imports -- $70 million over five years -- while more coin will be plowed into documentaries and news. There will be a drive to appeal to 10- to 15-year-olds and a $100 million fund to commission online public service content.

Additionally $20 million is being set aside for Film4, the web's movie production arm, recently responsible for "This Is England" and "The Last King of Scotland," plus another $20 million to fund and nurture new talent.

Said Lygo: "We will be showing more new programs in primetime than any other channel."

On paper, this all sounds mighty impressive. But when asked to be more specific about how Channel 4 thinks the public purse can pay for what its voluble toppers claim is a "funding gap" as advertising coin is divvied up between more and more players, there were tight lips all round.

"As we stand today, we do not have a preferred answer (over how the new money should be supplied) but we need to get there quickly," acknowledged Duncan, a former BBC marketing head. "We are doing all we can in terms of commercial efficiency and self help. Longer term it depends on replacing the subsidy we get (a reference to free transmission spectrum) with new forms of public support."

In Blighty, a consensus is building that Channel 4 should receive a small cut of the $6 billion or so from the license fee -- paid by all U.K. TV homes -- that funds the BBC. But skeptics, while acknowledging Channel 4's special place in backing risk-taking fare, take issue with the station's math.

Last year the broadcaster made a profit of $42 million, and while the channel, like all U.K. terrestrial webs, is losing audience share (down from 9.7% in 2007 to 7.9% this year) some veteran industry watchers think that Johnson, Duncan and Lygo may be crying wolf.

"There is no agreement on how big Channel 4's deficit is likely to be," says Steve Hewlett, a media commentator who was an exec at the broadcaster. "The questions over whether the channel really will need -- or should be given, additional support and, if so, how much and how it might be delivered -- are very far from being resolved."

And that is a conundrum that even Channel 4's famous supporters cannot get to the bottom of.