This Practice Note provides an introduction to the Organisation for Economic Co-operation and Development (OECD)’s Multilateral Convention on Mutual Administrative Assistance in Tax Matters (MAATM). Types of administrative assistance under MAATM range from the exchange of information, including automatic and spontaneous exchanges of information, to the recovery of foreign tax claims. For an introduction to the CRS, see Practice Note: Automatic exchange of information—the Common Reporting Standard: a summary. What is the history of the MAATM? The MAATM was first developed in 1988 by the OECD and the Council of Europe. As international trade barriers were reduced and capital became more mobile it was recognised that co-ordinated effort between states was necessary to combat tax avoidance and tax evasion on an international level. The MAATM provides for a single legal basis for bilateral and multilateral cooperation and allows for extensive forms of cooperation between competent authorities on a wide range of taxes. The MAATM provides for the exchange of information on request, spontaneous exchange of information as well as automatic exchange

STOP PRESS: On 5 January 2026, the OECD published the Side by Side package, consisting of: (i) a new simplified ETR safe harbour, (ii) a 12-month extension of the existing transitional CbC reporting safe harbour (which was due to end on 31 December 2027), (iii) a new substance-based tax incentives (SBTI) safe harbour, which allows for certain ‘qualified tax incentives’ to be treated as an addition to covered taxes, (iv) a new side-by-side safe harbour (SbS safe harbour) that applies to groups where the parent entity is located in a jurisdiction which levies a minimum level of taxation on the group’s domestic and foreign operations and (v) a UPE safe harbour for jurisdictions that only meet the domestic part of the eligibility criteria for the SbS safe harbour. For more information, see The OECD’s Pillar Two side-by-side package (2026): Tax Journal, Issue 1737, 10. In October 2021, the member states of the Organisation for Economic Co-operation and Development (OECD)/G20 Inclusive Framework on Base Erosion and Profit Shifting (BEPS) (the Inclusive Framework)

In October 2021, the member states of the Organisation for Economic Co-operation and Development (OECD)/G20 Inclusive Framework on Base Erosion and Profit Shifting (BEPS) (the OECD Inclusive Framework) reached agreement on a ‘two-pillar’ solution to the tax challenges arising from the digitalisation of the global economy. The two pillars represent an ambitious attempt to reform and modernise international tax rules that determine where and how profits are taxed. Pillar One is mainly (but not solely) focused on the digital economy: ‘a world where enterprises can effectively be heavily involved in the economic life of different jurisdictions without any significant physical presence and where new and often intangible value drivers more and more come to the fore’. Pillar One introduces two elements: • a new taxing right that goes beyond the traditional tax nexus rules based on physical location (Amount A) • a standardised methodology for transfer pricing baseline marketing and distribution activities between related parties (Amount B). This Practice Note provides a high-level summary of: • the tax challenges addressed by Pillar One • the underlying

Background The Office for Environmental Protection (OEP) is a public body that protects and improves the environment by holding government and other public authorities to account in England and Northern Ireland. Its origins are found in a 2018 Department for Environment, Food and Rural Affairs (Defra) consultation on ‘Environmental Principles and Governance after the UK leaves the EU’. This proposed ‘A new, independent and statutory body holding government to account for the environment’ to replace the European Union (EU) oversight and enforcement arrangements that would end when the UK left the EU. The proposals were developed in the Draft Environment (Principles and Governance) Bill, which then evolved into the Environment Act 2021 (EA 2021). Environment Act 2021 The EA 2021 received Royal Assent on 9 November 2021. For information on the development of EA 2021, see Practice Note: Environment Act 2021—developments [Archived]. EA 2021, ss 22–49 and Schedules 1 and 3 establish the OEP and set out its functions. The OEP came into existence on 17 November 2021. Prior to this the Interim

The Higher Education and Research Act 2017 (HERA 2017) represents perhaps the most significant legislative change to affect the UK higher education sector since 2004. HERA 2017, Pt 1 establishes a new regulatory body for higher education (HE) in England, the Office for Students (OfS) and makes provision for a new register of providers. More detailed information on the constitution and operation of the OfS is given in HERA 2017, Sch 1. HERA 2017, Pt 2 covers other education measures including student financial support, complaints and the deregulation of HE corporations in England. HERA 2017, Pt 3 concerns research, establishing UK Research and Innovation (UKRI) and setting out the research and innovation functions of the councils. More detailed information is given in HERA 2017, Sch 9. HERA 2017, Pt 4 picks up general matters, including co-operation and information sharing between the OfS and UKRI, transitional arrangements and pre-commencement consultation. Establishment of the OfS The OfS is a corporate body established by statute. It is not to be regarded as the servant or agent of

This Practice Note sets out Ofcom’s role in connection with electronic communications networks, services, radio spectrum, broadband and online safety. Ofcom was created under the Office of Communications Act 2002. Its functions (and duties) were established mainly by the Communications Act 2003 (CA 2003). Following the enactment of the Online Safety Act 2023 (OSA 2023), Ofcom is also the regulator for online safety, affording it additional functions, duties and powers. Ofcom therefore has regulatory functions over: • electronic communications networks, services and radio spectrum • television and radio services, including the licensing of television reception and the regulation of video-sharing platforms • competition in communications markets, and • online safety For guidance on Ofcom’s role under OSA 2023, see Practice Note: The Online Safety Act 2023. EU regulation and Brexit Part of the reason for the creation of Ofcom was the requirement for EU Member States to ensure that a competent body was made responsible for the tasks assigned to national regulatory authorities (NRAs) by the following directives, which originally comprised the common regulatory framework

The Office of the Public Guardian (Scotland) has announced that when a power of attorney document or an order is received for registration, it will now only record the legal name for all parties stated in the document. The forename, middle name and surname for each person as stated in the documentation will be recorded, thus the legal name will appear on the certificate of registration/appointment.

The Official Solicitor (OS) is an officer of the Supreme Court appointed by the Lord Chancellor. The OS's staff includes a number of experienced solicitors who specialise in Court of Protection proceedings and whose experience and practical knowledge not only assist the court and the protected party (P) but also any other party to the proceedings. The OS may, for instance, advise the court on an aspect of its powers or procedures or liaise with other parties to clarify issues, make suggestions and assist with achieving a consensus between the parties where possible. The OS represents minors and those who lack capacity in legal proceedings, but only when there is no other suitable person or agency available to take on this role. The role was established to ensure that the welfare, property or status of P is properly safeguarded. In Court of Protection property and affairs matters, this typically means acting as litigation friend, often in statutory Will or gift applications, or acting as property and affairs deputy of last resort. For further guidance

This Practice Note provides guidance on when it will be appropriate for the Official Solicitor to be appointed as a litigation friend in family proceedings and the requirements and procedure for such an appointment. It also addresses the issue of funding and costs. The Official Solicitor is an officer of the Supreme Court appointed by the Lord Chancellor. The Official Solicitor's staff includes experienced solicitors who specialise in Court of Protection proceedings and the representation of minors and those who lack capacity in legal proceedings, but only when there is no other suitable person or agency available to take on this role. It is important to note that where an application is made for the Official Solicitor to be appointed as a litigation friend, provision must be made for security for the costs of legal representation of the protected party to the satisfaction of the Official Solicitor. Further, that the Official Solicitor will only be appointed as a last resort, where no other person is willing to act as litigation friend, or in very exceptional cases. No person, including

Brexit Impact As of 31 January 2020 (exit day), the UK ceased to be an EU Member State. However, at this point in time, the UK entered a transition/implementation period during which it continued to be treated by the EU as a Member State for many purposes. 11 pm (GMT) on 31 December 2020 marked the end of the Brexit transition/implementation period. At this point in time (referred to in UK law as ‘IP completion day’), key transitional arrangements came to an end and significant changes began to take effect across the UK’s legal regime. Any changes relevant to this content will be set out below. Upon IP completion day, the European Union (Withdrawal) Act 2018 (EU(W)A 2018) created a new category of domestic UK law—retained EU Law (REUL)—made up of EU-derived rights and legislation that were preserved in the UK following Brexit. On 29 June 2023, the Retained EU Law (Revocation and Reform) Act 2023 (REUL(RR)A 2023) gained Royal Assent. REUL(RR)A 2023 reforms the treatment of REUL by: • revoking substantial amounts of REUL from 31 December

What are OFTOs? Offshore Transmission Owners (OFTOs) are the owners of offshore transmission assets which connect offshore wind farms to the onshore electricity network. The transmission assets comprise everything between the offshore point of connection with the generating wind farm assets and the onshore point of connection with the onshore network (including all cables and associated connection equipment). The assets typically include any offshore platforms and associated substations, export cables, the onshore substation and onshore cables to connect to the Distribution Network Operator substation. For more information on the different entities in the Great Britain (GB) onshore and offshore transmission market, and where they fit into the wider GB electricity market, see Practice Note: The Great Britain electricity market—an introduction. Introduction to the OFTO regime The legislative framework In 2011, the EU Third Energy Package was implemented in the UK through the Electricity and Gas (Internal Markets) Regulations 2011 (2011 Regulations), SI 2011/2704 and introduced the requirement of ‘ownership unbundling’, including the obligation that the ownership and operation of transmission systems be

NOTE: On 2 December 2024, the Lord Chancellor announced that the discount rate would change to positive 0.5%. The positive 0.5% discount rate is effective from 11 January 2025. Schedule A1 to the Damages Act 1996 provides that each subsequent review must be started within the five-year period following the last review. For these purposes, a review is concluded when the Lord Chancellor makes the determination as to the