John Bull

Hi, Any of you knowledgeable types out there know the provenance of a thoroughly pleasant pint which washed up at the Bold Forester recently identified only as John Bull?There was no other info on the pump-clip other than "traditionally brewed"and,surprisingly,after being forced into investigating,our excellent barman reported no further id on the cask.Would be grateful for the shedding of any light. Cheers, Chris