The 'grey' peas here aren't a modern import — they're an old variety of field pea that's been grown and eaten in the Black Country for generations.
Dried grey (maple) peas are soaked and slow-simmered until tender, then served in a bowl with chunks of bacon and a knob of butter stirred through. Market stalls and pubs across the Black Country dish it out as a hearty, inexpensive snack.