A broad view of evidentiality is adopted, based on Chafe (1986) and Haviland (1987) which goes beyond the grammatical marking of the speaker’s or writer’s perceived sources of knowledge and reliability of these sources to encode, not only what the speaker knows and how s/he knows it, but also what can be taken to be an addressee’s state of knowledge. According to this view, evidentials are contemplated as interactive devices or resources for redefining common ground between interlocutors. They go beyond referential content to signal such meanings as confrontation and contradictory assumptions. They are necessarily situated in social contexts and have an indexical function. They may also overlap with epistemic stances and with affect, ranging in the case of surely from surprise, disbelief, doubt and disapproval to persuasion and an invitation to share beliefs or to agree on future courses of action. Using data from the British National Corpus, I analyse a sample of concordances of surely with subject personal pronouns, with the aim of providing a preliminary characterisation of the range of interpersonal attitudes expressed by surely and the determining factors which trigger these apparently contradictory stances.