This paper presents the paradoxical co-existence of secrecy and transparency in the English justice system through the analysis of the concept of legal professional privilege (LPP). It starts by examining a definition of LPP as a protection from disclosure attached to the communications that took place between someone and a legally consulted lawyer. Then, it focuses on the two forms of LPP, legal advice privilege (LAP) and litigation privilege (LP), two legal situations which, though not the same, grant immunity to compulsory disclosure to all privileged (i.e. confidential) communications. Finally, the paper concentrates on the legal requirements to acknowledge LAP namely the fact that communications or other documents have to be made for the purposes of legal advice (Balabel v Air India) and advice has to be related to the rights, liabilities, obligations or remedies of the client (Three Rivers N°6). By presenting the steps of English civil proceedings (how to disclose documents and how to withhold inspection), the author highlights the apparent conflict between LPP on the one hand, and transparency and disclosure embedded in the rules of the English justice system on the other hand. The article then moves on to examine how the intrusion of secrecy within the supposedly transparent English system may jeopardize the fairness of the proceedings and the general public interest that “requires that in the interests of a fair trial litigation should be conducted on the footing that all relevant documentary evidence is available” (R v. Derby). The paper offers a reading of key cases related to LLP, stressing the fact that LPP and professional secrecy constitute predominant public interests vital to the establishment of a relationship of confidence between lawyer and client. The article ends with the somewhat unforeseen conclusion that transparency (that is to say full trust and unrestrained communication between client and counsel) is sometimes only preserved through secrecy and confidentiality. LPP is a powerful way to guarantee the quality of the legal advice provided by a lawyer to his client, a means also to avoid deceit and lies and to ensure an efficient justice system. Within the English legal context, secrecy and trust are intertwined, the former being a necessary requirement to the very existence of the latter.