I am Cornish and Welsh, why have I not heard of this?TBS
Eeee, I can answer up that 'un, lad! I was writing from old memory, and thee got me worried, so I checked. Here's Wikipedia on the topic. but I'll quote the relevant part:
The dish is traditionally held to have originated from the village of Mousehole in Cornwall and is traditionally eaten during the festival of Tom Bawcock's Eve to celebrate his heroic catch during a very stormy winter. According to the modern festival, which is combined with the Mousehole village illuminations, the entire catch was baked into a huge stargazy pie, encompassing seven types of fish and saving the village from starvation. The story of Bawcock was popularised by Antonia Barber's children's book The Mousehole Cat, which featured the star-gazy pie. In 2007 contestant Mark Hix won the BBC's Great British Menu with a variant of the dish.
(In other words, the pie version of the loaves and fishes miracle.)