I saw this both times when it was shown - when I was around 10 - and it started a lifelong devotion to John Buchan. As a working class Scottish kid, I could barely believe that I was watching a brilliant historical adventure story that featured heroes who came from my background and who weren't much older than me. All of the lads in my class at school loved it, too. The magnificent performance by the young actor who played Dougal, the leader of the Gorbals Diehards, still stays with me as a superb performance by a boy actor, and he captures much of the warrior-leader genius of the character from the novel.
The old guy who plays Dickson McCunn was also brilliant, too, as the elderly, mild-mannered retired grocer who discovers he's actually a hero. The memory of the final scene of the six Diehards saluting him as he drives past them still brings a lump to the throat and a tear to the eye.
Finally, David Wood as Sir Archibald Roylance is another great portrayal of a Buchan hero. (Wood was also the greatest ever Gollum - forget Jackson's LOTR in "The Hobbit" as adapted by "Jackanory".
I wish this would come out on DVD or be repeated so my own sons can see it.