A still from the opening titles of the first Newsnight
There's an advertisement for a beautiful and expensive watch which goes something like: you never really own one, you just look after it for the next generation.
That's more or less how it feels to edit Newsnight.
After 25 years the identity and purpose of the programme I watched for the first time as a teenager in 1980 remains indelible.
The 11 editors who have looked after it over the years have taken it in all sorts of different directions - from a rainforest recreated in the studio to a camper van on the election trail - but I think they, the programme team and our viewers have always had the same clear sense of what it's for.
As we started thinking about Newsnight's 25th anniversary we pulled the first-ever programme out of the archive. The music was roughly the same, the graphics pretty clunky and the pace of the programme notably slower than it is today.
'Welcome to Newsnight, at last...'
But it was obviously the same programme, setting out to do the same things: to make sense of the day's news, to try to explain the detail of current events and hold to account those responsible for them. To make you think again.
Peter Snow was there, and so was David Sells, reporting the programme's first foreign film, about Oman. His most recent film for us was just last week, about Iraq.
I don't think it's a coincidence that Newsnight was dreamt up in 1979. It was the era of radical political upheaval, new wave music, the Fall and Rise of Reginald Perrin. The birth of Channel 4 was just around the corner. Newsnight was invented to be a hybrid of news and current affairs, but for me its main aim was far more important than that.
It was to offer an alternative to the way news had until then always been done, to ask questions that politicians hadn't had to answer before (and eventually to keep on asking them until you got an answer).
An earlier version of Peter Snow's famous sandpit as used in the first programme
It was always determined to take a route other than Coleridge Close leading to Tennyson Avenue. I quickly became hooked on Newsnight above all because, like everything else I was interested in in 1980, it refused to conform.
The programme's first editor George Carey confirms all that in his contribution to this website. One of his only rules was that the programme shouldn't lead on the same thing as the Nine O'clock news.
George describes the lo-fi quality of some of the early programmes, exemplified by Peter Snow's magnificent sandpit which made its first shaky camera appearance - explaining the situation in the Afghan war with letraset and model shop tanks - in the very first programme. That tradition persists today.
Television news has a lot to be said for it, but Newsnight has always lived on the edge of that world. In news, nuances tend to be ironed out, blemishes covered up, stories packaged.
On Newsnight we aim to keep the rough edges, explain the awkward details, we celebrate the eccentricities of our correspondents and if, once on air, it doesn't always go entirely smoothly that's part of the deal.
On Newsnight, an item can be 30 seconds long or if you want it can be 49 minutes long. I can think of no other programme anywhere on TV where you have the same possibilities.
Over 25 years Newsnight has broken countless stories, produced ground-breaking and policy-shifting films, delivered many memorable interviews and a few excruciating televisual catastrophes. You can see a selection on this site.
David Sells reporting for the first Newsnight
And we've also had our critics. When I wrote recently that our aim was to offer "the best daily analysis of news and current affairs on television" one newspaper accused us of trying to be better than the politicians and other public figures who must be seen to be defeated. That's nonsense.
Our aim isn't to beat the politicians, but always to question the way things are.
When I first joined the programme as a trainee in 1990 the then editor Tim Gardam - one of the most intellectual to hold the post - explained that Newsnight was a programme in the best traditions of late 18th century non-conformism.
For me it's always been a programme in the best traditions of the late 1970s alternative movement.
I think we're both right, and somehow everyone who works on the programme - some of whom weren't even born 25 years ago - knows what it means.
Newsnight is broadcast every weekday at 10:30pm on BBC Two in the UK.