This refers to rumours, the argument being that all rumours are based on fact; that although some may doubt the accuracy of a report that is passing from mouth to mouth, there must be some truth in it, however little.
‘I hear Barglows are closing down their shop in West Street.’
‘Surely not! They’ve got a fine business there.’
‘Well, a number of people have told me that Barglows are feeling the pinch –and there’s no smoke without fire. ‘