I think it's a reference to "Hitchhiker's Guide to the Galaxy". Knowing Earth was going to be destroyed the dolphins leave, but they leave behind a message which when decoded translates to "so long and thanks for all the fish" (referring to how dolphins had trained humans to give them a fish when they did tricks).
happymellon|3 years ago
He thinks that the UK is going to implode?
Probably correct even if it is mostly harmless.
bigiain|3 years ago
Arguably, it's in the middle of doing so right now...