Wonderfully, hammily, lip-quiveringly bad, it looks like it's filmed in a theatre, and from their emotionally and syllabically resounding delivery, it seems the actors thought it was too. The best bit comes early in the first episode, a pure comedy diamond nestling amongst the Cornish coal of melodrama, as our tousle-mopped, ruddy-cheeked heroes descend the mines with long thin candles strapped onto their hats. No, not oil lanterns cunningly adapted to be early miner's lamps. Not even tealights snug in little holders. Skinny, tottering, dining-room candles, balanced on their heads.
Oh, it may well be historically accurate - I don't know and I don't care. It's pure, helpless, stomach-ache, little-bit-of-wee Monty Python brilliance. As is this.