Britain's fourth TV channel was created with a brief to do brand new things on television, and make trouble among the TV schedules.

The first face to be seen after the channel logo was Countdown host Richard Whiteley.

Over the years the channel became renowned for programmes such as The Tube, the Comic Strip and Brookside, as well as cutting edge documentaries.

More recent successes have included Big Brother and Peter Kay's Phoenix Nights.

However some think the channel has forgotten its challenging principles in an attempt to keep hold of viewers.

What are your memories of Channel 4 during the past 20 years?

This Talking Point has now closed. Read a selection of your comments below.

I'm a huge fan of C4, but their marketing annoys me now. They put all the best stuff on E4 and FilmFour - not the best way to keep terrestrial viewers, I feel!
Richard, UK

You can't criticise a channel because more people accept and embrace it's alternative remit.

Chris Merriman, UK

I think it's incredibly unfair to say that Channel 4 has lost it's way. We should celebrate that UK culture has become more diverse and accepting. Remember, shows like The Tube were so cutting edge at the time, they helped bring acts like U2, like Depeche Mode etc to a wider audience - and these bands are still breaking boundaries 20 years on. You can't criticise a channel because more people accept and embrace it's alternative remit. As far as I'm concerned, mission accomplished...
Chris Merriman, UK

The Comic Strip's hilarious take off of the 'Famous Five' in their 'Five go Mad in Dorset' was excellent. Can we see it again ?
Andy H, Lacock, Wiltshire

I always remember having to switch aerial cables to be able to use the correct aerial to be able to get Channel 4 during the early days. Since then I have been glad that they have brought us some of the programs that no-one else seemed to want to touch.
Nigel, Scotland

The greatest (and perhaps saddest) plaudit I can give Channel 4 is that without it Britain would have no film industry worth talking about. Film Four have been responsible for funding and televising some of the most imaginative and groundbreaking (and commercially successful) UK films over the last 20 years. Yes, it has become less cutting now, but it is always interesting, and if the alternative is an endless diet of ITV and BBC1 then let us have a hundred Channel 4s on air. Happy Birthday!
pip, UK

It has always stood by its ethos

mel, London

Channel 4 has always been groundbreaking and has always dared to produce programmes with content that no other channel would dare. It has always stood by its ethos and despite going close to the mark it has always been the definition of 'entertaining' since the word go. You must applaud Channel 4 for being controversial, amusing and always moving forwards. Plus it has Peter Kay.
mel, London

Channel Four - What a breath of fresh air it was in the 1980s. Experimental comedy, risk taking films and anarchic music shows. How times have changed. Now, the music's almost always insipid top 40 material, films aren't made if they won't make a commercial profit and the comedy (with the notable exception of Black Books and Phoenix Nights) has gone down the pan.

Perhaps C4 should be prepared to look back at the formulas that made it great. It should aim to make films and plays that will never see the big screen, re-invent Saturday Night Live and produce a live music show to rival Later, which is after all The Tube for grown-ups.
Giles Kendrick, UK

Channel 4 hasn't gone bland at all - Everything seemed better "In the old days" but really, in the past few years not only have there been crown-pleasers like the highly innovative "Big Brother", there has been great drama in the form of "Six Feet Under". I think they're getting just as right as ever, bringing us great home-grown entertainment and blending it perfectly with series from around the globe.
Sean Murricane, Leeds, UK

It seems to have lost its direction

Matt, UK

C4 has been at the forefront of Quality and diverse programming for many years. Now it seems to have lost its direction by showing bland, soulless commercial TV. The big brother period, even though sometimes entertaining, showed a low point in its years of broadcasting. I hope C4 will use this birthday to rethink its direction and focus. It has been a cultural crown jewel; I would love to think it could reclaim that crown! Happy Birthday Channel 4
Matt, UK

Only a channel as gutsy as Four would have given Brass Eye a platform. Hurrah for Channel 4. Please lose Hollyoaks though, it stinks.
wendy, UK

Channel Four began with such promise. The Comic Strip series, P'tang Yang Kipperbang and Walter were all signs of something new, diverse and different. Where did it go so bland?
Alan Sircom, UK

I applaud Channel 4 for having the guts to do what others wouldn't dare

Andrew Logie, UK

I applaud Channel 4 for having the guts to do what others wouldn't dare. They've risked reputation and jumped into many a pool of controversy, to bring us quality, unbiased, realistic television.
Andrew Logie, UK

In rural England, there was almost no coverage of gay issues or that gay people even existed except in the form of tabloid press "scandals" regarding celebrities and attacks by clergy on children. Hardly a positive role model to a teenager growing up "alone" with their sexuality. Scouring the TV schedules also revealed nothing until Channel Four ran a Gay Film season. Finding out through film that I was not "alone" and that there were also positive characters and above all futures out there and a future for myself, helped bring a fourteen year old up and boost his spirits which were incredibly low.
Mark, Germany,

Football Italia was my all time favourite Channel 4 program. When they didn't buy the television rights for this football season I knew that things weren't right.
Toby Evans, UK

I remember there were very few adverts and the time was filled with music and the picture of a number 4. How things have changed.
Richard Crossley, UK

I was hooked before it started. I watched all the test transmissions. Tour de France coverage (now dropped), Who Dares Wins, Chelmsford 123 and all the other Hat Trick Productions are my fond favourites. Please repeat them all.
James Butler, UK

Channel 4 has brought us some terrific TV programmes

Geoff Stafford, Manchester, UK

I was lucky enough to sit in the control room during one episode of The Tube. This was an exciting experience, especially when the outdoor camera on Jools Holland went down 60 seconds before the start of the live show and only came back on when the director told someone to 'kick the cable'! It's extremely sad to see what has happened to the regional ITV companies such as Tyne Tees, which made the Tube. Channel 4 has brought us some terrific TV programmes and films over the last 20 years but less so lately and I fear it is also going down the drain.
Geoff Stafford, Manchester, UK

I feel that Channel 4 has been in touch with the youth of our country far more closely than any other channel yet. The creation of Film Four and the success of many strong British films only highlights some of the achievements of the channel.
Nicholas Gardiner, Bournemouth, UK

Actually Channel 4's film contribution goes hand in hand with its TV achievements. Brookside being sidelined isn't a tragedy when the show that helped kill it, Hollyoaks, hails from the same producer. Being a groundbreaking channel doesn't rule out the need for progress after twenty years.
K Henry, England

A large group of us sat around a portable TV in the lounge of our halls of residence, at Derby Lonsdale College, and we watched the launch of Channel 4. Over the last 20 years I have enjoyed the variety of programmes and subject matter that C4 have provided.
Helen, Birmingham, UK

Where has all this incredible diversity gone?

Paul Williams, England

Channel 4 was very innovative in its first few years, and I watched practically nothing else when it first appeared. I was introduced to the marvellous animation of the likes of the Quay Brothers and Jan Svankmeyer amongst others, and practically every programme was a refreshing change to the lowest-common-denominator offerings of the other channels. C4 still has the upper hand I believe, but where has all this incredible diversity gone?
Paul Williams, England

Football Italia, Sumo and American football. Made popular by C4, and then, sadly, taken over by pay channels.
Bernard, UK

Channel 4 have made some fantastic shows that, throughout my childhood, provided so much entertainment and excitement. None more so than their adventure game shows - Treasure Hunt, The Crystal Maze, Wanted and Lost have all been fantastic shows that Channel 4 should be proud of....
Lee Beckett, UK