This game was big in the UK a few years ago. Originally impenetrable to non-Londoners - who of course had a far greater familiarity with the stations on the Underground - it became such a craze that people throughout the UK would study up on their tube maps and become as proficient as native Londoners. There are dozens of variations, each with its own conventions, but only a few were played widely. The cast of the comedy "I'm Sorry, I Haven't A Clue" are playing the Maldon variation here, which allows redoubles and laterals, or "slants."
This is a rather short game which they stretch out with patter in between moves. Cryer and Hawks are reportedly very good players, actually, though they keep it simple here. Or so I'm told. I can't tell the voices apart myself, and it's a pity there's no video to go along with this. Tube maps are not available during competitions - all players must work from memory. I can't follow a bit of it without the map myself, so I imagine you won't either and I have included an expandable one for reference here. Index here.
No matter the sequence, all answers produce at least some points; but like Scrabble, you can set up high-scoring moves with earlier, innocent-looking ones.