Kukrit grubs are rather nice, basically a chewed up kukrit nut inside a skin sac but they're not a UK thing.
In my younger days a mate and I dared each other to eat maggots whilst we were out fishing, they weren't too bad really - they'd been purged with bran rather than feeding off rotten meat.
So called, when I was a toddler I couldn't be left alone in the garden because I'd upend the stones and eat worms and woodlice. I have no recollection of this though.