On paper, it's not hard to make a documentary - you just need to find the middle ground between education and entertainment. In practice, that find line has proven a little more difficult to find - especially when your subject matter is a little niche. If you want to know how to get it right, pick up a copy of Metro-land.
On the face of it, this could be the quite an ordeal - an old poet takes a trip through London's regional and rail expansion of the 1930s, telling us all that life's not as good as it used to be. But it's so much better than that - in fact this piece of 30s nostalgia has taken on an added dimension today as a piece of 70s nostalgia.
The poet in question is Sir John Betjeman, taking us on a rail trip along the Metropolitan railway, kicking off at the (already closed) Marlborough Road station, heading through Neasden, Wembley, Harrow, Chorley Wood and through to the end of the original line, Verney Junction.
Along the way, we find out about the suburban housing programme that accompanied the rail expanse and take in a selection of life and history, including Wembley Stadium, Watkins Folly (London's doomed Eiffel Tower rival) and the British Empire Exhibition (some of which was still standing in 1973 in the Wembley area), as well as dropping in on the Moor Park golf club, Grim's Dyke and the Byron Luncheon Club in Harrow. There's even time for a glimpse at the modernist High and Over house.
It's fascinating viewing. Not the most exciting TV you'll ever see - but it was never meant to be. Metro-land captures a moment in time, with a mix of stunning scenery, interesting history and the words of a man with a genuine love of the area. Anyone with an interest in 70s life should watch Metro-land. And if you're a documentary maker, you should watch it at least once a month.