For those that don't know - and I didn't until not that long ago - the film of Frost/Nixon is based on a stage play of the same name, which in turn is based on the interviews David Frost conducted with Richard Nixon in 1977. The intermediate step - the play - is I think crucial to understanding why the film is as it is. Plays tend - and stop me if I'm generalising - to be aimed at an older audience than movies. Especially plays with intellectual ambitions like Frost/Nixon. The play isn't aimed at the multiplex and by being faithful to that play (an assumption of mine since I've not seen the play) the film isn't aimed at the multiplex either. Which is an irony as the interviews themselves had such mass appeal that they set audience records for political programming which stood for many years (and may still stand today depending on your definition). But the interviews exist on film - indeed they can now be bought for a shade under fifteen pounds if you're so minded - so recreating them seems pretty pointless. David Frost - whatever you think of him (and who doesn't?) - is a better David Frost than Michael Sheen. He can't help it - it's in his genes. So the play (and film) has to be about more than just the interviews. That is where both its strengths and its weaknesses lie.

The cast is excellent - bound to be after so many performances on the stage to really nail their characterisations. Rather than doing your actual impressions, they create subtly new interpretations of the two men at the centre of this cascade of candour (as Frostie put it in a particularly smiley moment). David Frost - and probably Nixon as well - is impossible to impersonate without descending into a absurdity by the second word. It's like anyone being able to impersonate Frank Spencer but only Michael Crawford can actually play him. My only criticism of Sheen's performance (and it isn't really a criticism) is that it reminded me too much of his Brian Clough. The hair was a little longer and the shirts a little more glamorous but the voice was almost the same, the smiling self confidence was almost the same and the glint in the eyes was almost the same. They were both excellent performances and you can't invent characteristics that weren't there just to differentiate two different characters in two different films (Frost can't suddenly have an eye patch and Cloughie can't suddenly be a limping black man from Swansea) but I found it a little bit off putting. And, having really enjoyed "The Damned United" it was always going to make Frost/Nixon come off as second rate.

But that's a mere trifle - the real flaw in the film is that it assumes too much of its audience. This is what I meant about the film's theatrical origins meaning it aimed higher than the multiplex. Maybe it's just me but I found it relied on the audience knowing the Nixon affair in some detail. Not so much facts and dates but just what you'd gain by living through it. I'm simply to young to be able to understand what all the fuss was about. I can read about Watergate, I can see footage of Vietnam protests and I can hear people saying how much they loathed Nixon but I don't understand it. Not in the same way I'd understand a similar film about Margaret Thatcher or Ronald Reagan. The film had - I think - a duty to give some background information on what it was they were talking about. "The Damned United" (sorry but it is the best comparison) didn't assume the audience knew a lot about 1970s football. They used footage and subtitles to give the audience just enough so that they'd know what was going on and why it was important. Frost/Nixon gave us snippets of low level detail - dates, times, surnames - but that's all. And we don't really care about that - the interviews themselves are about the details - the film is about the men and what they did to be who they are at that point in time.

The sad thing is that the film has the exact means to deliver this context info - the talking heads which occasionally appear to talk about those events. They seem to be used to make the whole thing look like a documentary but they largely just described what we were seeing. I would much rather have had them - subtly - explain the background to what we were seeing. If Nixon is talking about the Vietnam protests, why not tell us why people were protesting. I know they were protesting against the war but why was Nixon such a target when he didn't start the war? They mentioned in passing his dealings with Russia and China - they were off-handedly cited as successes for Nixon but why? What happened? There was still a cold war at the end of Nixon's time in the White House so how did he have success?

It only takes a couple of lines to set everything in context. Nixon said this but then did this and people felt this because of this. Adding talking heads to do this might interrupt the flow but they were already there and being used for something less important so why not? I suspect the reasons are (a) the earlier point about it being aimed at people who remember Nixon's reign because they lived through it and (b) it's one of those things that Americans know about and they wanted the film to do well there. Sod the rest of the world.

And before you say that I could look it all up, that's not really the point. It doesn't matter if I know about it now - days after the fact - I needed to know it then. If I don't know what Nixon did wrong and why everyone hated him, it doesn't mean anything to me that his facade cracks and he sort of apologises for and sort of admits to various things. Remember, I'm jaded after twenty years of political decline. The President lied and tried to cover up for something illegal. Big deal. The last President was a war criminal who stole two elections. A few quips on a tape about taking care of things don't impress me much (as Shania Twain once observed for posterity).

In the end though it isn't a film about Richard Nixon - it's a film about David Frost. A man who had the vision and drive to get this project off the ground and who then found he'd overstretched himself when the consummate politician turned out to be better at sabotaging television than Frost was at making television. By the end, he gets what he wants thanks to the team he's put together. Facts have been twisted slightly to make a more dramatic time line but it's basically what happened. The interviews - for so long looking like a failure - turned out to be a success. Frost pops the champaign and goes on to be the most famous interviewer in the world. Nixon slips away from public life. All the while, in the background, Tom Quinn from Spooks is playing the man who would do so much to dismantle all that was great about the BBC, John Birt.

Despite all of the above, I did enjoy it. The two hours flew by and it's made me interested enough in those concerned to get Frost's book about the making of the interviews. If you tell yourself that it doesn't really matter what they're talking about - what matters is the way the dynamic of the interviews shifts from Nixon to Frost at the last minute - then it's a great film. If you pretend that those portrayed are fictional characters and we're not meant to know all the background of the president character (shades of grey and all that) then it's a great film. But if we're meant to care about what Nixon says and what he ends up sort of apologising for then it isn't a great film because anyone under 40 and not American is going to struggle to know or care about it. Nixon the character seems like a nice chap. There is nothing in the film to make us dislike him. The delight that his on-screen breakdown causes just looks a bit distasteful out of context. We don't cheer when Frost wins because he's beaten Nixon but we do cheer when Frost wins because we like this David Frost guy. He seems like fun. In fact, both Frost and Nixon both come out of this film seeming like better people than their reputations suggested going in. I don't think that was the idea but since we were never told why Nixon was such a heel then it's hard not to vaguely warm to him.