Its working title was The Travelling Post Office and Basil Wright was assigned to write a script on the subject. I read some of his early notes. I recall vividly his suggestions for the now famous Beattock sequence, immortalised by Auden's verse:

Basil's equivalent, scribbled in one of those large Post Office notebooks, read roughly as follows:

Over close shots of the locomotive's funnel belching smoke as it struggles up the Beattock gradient, the puffs get slower and greyer and maybe we could lay over a voice saying; ‘I think I can, I think I can’.

Whether he ever finished that script I don't know. Certainly I never saw it. Neither, I suspect, did Harry Watt and I was with him on every shot in the making of Night Mail. However, during the birth pangs of this recognised classic, when the search was on for an idea, a conception of how to tackle the subject, John Grierson came down to the pub at the end of Bennett Park Road where seniors and juniors would gather to discuss the day's work and generally put the world to right. We juniors would make our half pints last as long as possible, listening to the great minds at work, and there were some great minds at work: Humphrey Jennings not the least of them. Grierson had been talking about documentary and possible lines of approach to tackle this ‘Travelling Post Office’ subject, our most ambitious and complex one to date.

He summed up and I can almost quote him verbatim, even though I heard his words over 60 years ago.

Can we imagine a society without letters? Of course we can't. But does anyone appreciate the postman? Of course not. We take him for granted like the milkman, the engine driver, coal miner, the lot of them. We take them all for granted, yet we are all dependent on them, just as we are all interdependent one to another. It has nothing to do with class or education.