The channel has already won Baftas and Royal Television Society awards for Sex Traffic, a one-off film about two Moldovan sisters swept up into illegal trans-European prostitution rackets, and Omagh, the story of the car bomb that killed 29 people in Northern Ireland. At last week's Monte Carlo Television Festival, Omagh scooped another four awards. The Government Inspector, a drama about the life and death of Dr David Kelly, and The Hamburg Cell, which showed the human face of the 11 September bombers both attracted critical acclaim.
Drama chief Tessa Ross has just returned from yet another pitch on the current affairs obsession of the moment - Africa - with at least one drama already in development on the problems facing the continent.
Recent audience research shows that when questioned on current affairs, Channel 4's audience talk about its dramas. But the last thing Ross wants is for people to pigeonhole the channel's one-off dramas as depressing and obsessed with current affairs.
She says: "That would be awful and people would start switching off. We have got an absolute appetite and hunger for dramas that we hope will have impact. Film-makers and writers are looking to their daily lives, and there seems to be a lot more going on in the world - the questions about the war, about America." Lighter fare on the forthcoming slate of single dramas includes The Queen's Sister, a humorous take on the life of Princess Margaret, and Elizabeth I, a historical drama about the Virgin Queen with a contemporary feel.
Channel 4's drama series are also considerably more easygoing, although just as capable of collecting gongs. Shameless, Paul Abbott's hit drama about a family of lovable rogues living on a Manchester housing estate, has accumulated an almost embarrassing glut of accolades, while Rhys Ifans was rewarded with a best actor Bafta for his portrayal of comedian Peter Cook in Not Only But Always.
For a long time, Channel 4 had a poor reputation in drama because, with the exception of intermittent hits such as Queer As Folk, it lacked the resources to invest in the genre. Michael Jackson, the channel's then chief executive, brought in Ross in as head of drama in 2000 to create a strategy for contemporary, risk-taking pieces.
She admits: "At that point, we asked, did we have a track record in drama? The answer was no we didn't. We had quite a low reputation. So we discussed how we could build a consistency and a volume and an attitude. That took a fair amount of time to deliver and the luck of it is that the best of that work came out in the same year."
In the spring, Channel 4's director of programmes Kevin Lygo announced an additional investment of £13.5m in single and serial drama next year, with a view to producing a landmark event drama every month by 2006. At present there are four big one-off dramas a year, costing between £1m and £2m to make, and between four and five drama series, at a cost of around £4m each. A pattern is emerging, but Ross is determined it should not become a straitjacket.
"It's always about authorship. When we get it right, it's about supporting somebody else's vision. If one applied one's own prescriptive vision and said: 'What I'd like is four light-hearted long-running series and four politically motivated events,' you would already be limiting the imagination of those people you are trying to liberate.
"People now have more of a sense of what Channel 4 stands for in drama. It questions. It asks about the world in a way that it hasn't been approached before. That can be a mixture of entertaining, frightening, or extremely funny. You can range across bold colours. We're never pastel."
Unlike the BBC with its trademark lavish costume dramas, Channel 4's output is overwhelmingly contemporary. Ross prefers to point to think of it as "contemporary in spirit" and points to the forthcoming Elizabeth I, starring Helen Mirren as the monarch in later life.
"That is a view of a woman at a particular point in her life, questioning how she can hold on to power. Can she have an heir? Can she still have children? It shows Elizabeth at a point in her life where I don't think one has seen her before, where she might lose power. "
The channel has not lost its power to offend. No Angels, a fictional account of four young nurses living in Leeds, was attacked by the Royal College of Nursing for portraying the profession as full of sex-mad, drug-taking ladettes. "Teachers came in for quite a lot of criticism from the teaching community too," says Ross. "The point of No Angels was not to say all nurses are this way. It was a wonderful story about young women and friendship and life."
In 2002, Ross moved to head up Channel 4's film division FilmFour when it was brought in-house. Then in January, when her successor as drama chief, John Yorke, returned to the BBC to oversee EastEnders, she was appointed to oversee both television drama and film - a move intended to increase cross-fertilisation. "The brilliant thing about how we are structured now is that people can come through one door and anything is possible within that," says Ross. In her new role, the 43-year-old mother of three, who read Chinese at Oxford University and was previously head of BBC drama commissioning from independents, is able to pool talent from the worlds of film and television.
"Film can now be bedded into the channel and become part of the DNA. If you're commissioning comedy and one of the talent you are working with wants to develop, write and direct their first feature film, it now becomes possible for that talent to grow into film internally and cosily," she says.
FilmFour invests £10m a year - as much as the BBC - in films such as Touching the Void and The Motorcycle Diaries. The Last King of Scotland, a film about Idi Amin starring Shameless actor James McAvoy and directed by Touching the Void director Kevin Macdonald, has just started filming in Uganda. The division had three films entered in the Cannes Film Festival, two by British-based directors, leaving Ross disappointed by the criticism over the lack of UK films in the competition.
In spite of recent successes, Ross is nervous about whether Channel 4 can continue to come up with hits. She believes the only solution is to change or die.
"It feels like 'Oh my god, we'll never do it again'. There must be very good reasons for success and there must be very good reasons why we mustn't do it the same way again."
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