it was a beer commercial - carling I believe, in which football was invented. man flashes something horrible under his coat to doctor type person, who drops his beer in shock, can gets kicked, whole crowd joins in...was that the one you were thinking of?
No, I don't think so, it was definitely a medieval street market scene. There was an exchange along the lines of 'I bid you one stoat' they settled on 'one ferret' and the catchline then was 'got change for a guinea pig?' Possibly an ad for a bank?