The Law Society has published FAQs on HMRC’s mandatory tax adviser registration requirements under Part 7 of the Finance Act 2026, which received Royal Assent on 18 March 2026. The requirements apply to solicitors who ‘interact’ with HMRC on behalf of clients, including most residential conveyancers who file stamp duty land tax (SDLT) returns. The FAQs indicate that outsourcing SDLT filing is unlikely to exempt firms from registration requirements, as paying SDLT to HMRC would still constitute ‘acting as an agent’. HMRC’s digital registration system is expected to launch on 18 May 2026, with firms given three months to complete registration. Registration will generally apply to firms rather than to individual solicitors, although firms must designate ‘relevant individuals’ at the point of registration based on the firm’s size and management structure. Eligibility requirements for registration include evidence of anti-money laundering supervision, no outstanding tax returns or unpaid tax and no relevant unspent fraud or tax offences, among other factors. Failure to register or comply with registration requirements may result in financial, operational and regulatory consequences, including the inability to communicate with HMRC.