Former chairman of the Conservative Party
It is still a great newspaper. I wrote for it for a number of years and what I found was that The Sun presents complex ideas with a fairly limited vocabulary and that's tough journalism. I think a mark of its quality is its political editor [Trevor Kavanagh]. He doesn't stay there for nothing, you know. He thinks it still has influence, and so do I. Yes, it is capable of being vulgar and over-the-top, but the excesses are rare.
Sir Gerald Kaufman
Chairman of the Culture, Media and Sports Committee
It is, without doubt, the most influential newspaper published in Britain today. Forget so-called opinion-formers; I am interested in the people who actually elect me. It consistently hits the spot in the way that its competitors don't. No newspaper gets everything right all the time, but The Sun comes close.
MP for Maidstone and the Weald
What can one say about The Sun? Well, it serves a market. I know that whenever I have been asked to write for the newspaper I just haven't been able to. I can write Mail-ese, I can write Express-ese but I just can't do Sun-ese, which involves very small sentences of words of no more than two syllables. It writes from its gut instinct and says what people are thinking. I think page 3 is demeaning to women and I think they should get rid of it, but there is not much else I would change. I remember being struck dumb in the newsagents when I saw the "Up Yours Delors!" headline. It was tacky but it was brilliantly tacky.
MP for Halifax and campaigner against The Sun's page 3
The Sun isn't a newspaper that I like. I think it almost goes out of its way to degrade women. If you take page 3 as an example, it's an idea whose time has passed - it's terribly old hat. They never had a particular go at me but I was caught up in the general mêlée when Clare Short and I and some others tried to get them to stop it. As for its politics - well, people say they support Labour but they don't. They support No 10 which is not the same thing at all. On the Iraq war they were appalling. Appalling and wrong. And we were right, weren't we?
Co-author of 'Stick It Up Your Punter', a history of the paper
It's probably less influential now than it was, but it's still very powerful. Clare Short told me that David Blunkett would shake with fear when he thought about how his policies would play with the paper. It's a negative kind of power, though, a kind of veto it has. The Sun can't put anything on the agenda - for example, if it decided to get behind the Green Party everyone would just ignore it. But if it goes negative on you, you've got a problem. It proved it with Foot, and Kinnock and then Major. The Sun is the nearest thing we have in this country to the political adverts that decide US elections - the demolition jobs and character assassinations that would not be allowed in an advertising campaign in this country. Then again it only has power because politicians believe it has power. If they just ignored it maybe things would be different.
Chairman of PR firm Bell Pottinger and formerly Margaret Thatcher's election adviser
Its political influence was greater when it was more unpredictable. It had a different way of looking at things. Now there are so many more products in the media that are trying to be versions of it. That's where a lot of its influence lies - on the rest of the media, right through to the BBC. The way they report things has been copied. Content on television - celebrity gossip and reality rubbish - bears a closer resemblance to The Sun than to any other newspaper. I still love it. It's brilliantly put together. It's just difficult for it to go on being ground-breaking.
Former chairman of the Parliamentary Labour Party and privacy law campaigner
It's changed journalism but not, I think, for the better. It was in the gutter for a long time. To be fair it has improved recently. Not just because it supports Labour but because it made itself believable in a way that it simply wasn't during the Kelvin MacKenzie era. As for the future, I think David Yelland was right. It's old market is disappearing and it's got to pull itself upmarket somehow.
Critic and writer
It seems to be a very fragile newspaper, probably the most fragile. It has Trevor Kavanagh, the Political Editor, who commands huge respect and then there's the rest of the paper. It does show you a lot about the power interest in the UK. It has a number of constituencies, which it has to keep happy. It must have access to power and keep its circulation. So, the need to keep all those balls in the air makes it fragile. I don't think it does more harm than any other paper, or any more good. It has this particular remit of being the biggest-selling paper in the country, and it has to be that way.
Interviews by Francis Elliott and Simon O'HaganReuse content