Acting against a former client whose confidential information you hold (SRA Code paras 6.3-6.5)

Paragraph 6.3 of the SRA Code of Conduct for Solicitors, RELs, RFLs and RSLs requires solicitors to keep the affairs of current and former clients confidential unless disclosure is required or permitted by law or the client consents. Paragraph 6.5 provides that a solicitor must not act for a client in a matter where that client has an interest adverse to another current or former client of the solicitor or their business, for whom confidential information material to the matter is held, unless (a) effective measures have been taken which result in there being no real risk of disclosure, or (b) the client whose information is held has given informed consent, given or evidenced in writing, to the solicitor acting, including to any protective measures. Petra's interests are adverse to Lyndon's and the firm holds material confidential information, so it can act only if one of those conditions is met.

Why A is wrong: Para 6.3 expressly extends confidentiality to former clients.

Why B is wrong: The para 6.4 duty to tell a client of material information does not override the para 6.3 duty to keep Lyndon's affairs confidential, which applies unless the law requires or permits disclosure or Lyndon consents; this tension is why para 6.5 restricts acting at all.

Why C is wrong: Under para 6.5(b) the relevant consent is that of the client whose confidential information is held (Lyndon), not the new client.

Why D is wrong: Para 6.5 permits acting where there is no real risk of disclosure through effective measures, or with the informed written consent of the former client.