## 1 Introduction  
Distributed ledger technology is a major catalyst for change in the money system and the administration and control of money. Furthermore, DLT offers promising potential for disrupting the existing information management frameworks of government departments, such as the Bank of England (BoE) and His Majesty's Revenue and Customs (HMRC), in order to overcome the friction of public policy decision making. DLT's are already being employed in diverse business applications and have matured significantly since the inception of the first established network of this kind, Bitcoin [1]. This is the first and most popular digital currency and payment system employed on a DLT platform [2] and was the first of its kind to eliminate the need for a single entity that accounts for and controls a currency [3]. Its success has led to a market capitalisation that peaked USD 1.43 tn in March 2024 and the subsequent emergence of numerous alternative digital currencies (also known as cryptocurrencies or cryptoassets) such as LiteCoin, Ethereum, Ripple, and Bitcoin Cash. The success of digital currencies is attributed to the perceived failures of governments and central banks during the 2008 financial crisis, including serving as cheaper alternatives to existing debit and credit card systems [4]. Just as with cash, i.e., banknotes, digital currencies are considered a medium of exchange, a store of value, and units of account [5]. However, the adoption of de-regulated cryptocurrencies creates problems associated with the volatility of cryptoassets, which poses a risk for buyers and sellers; the risk of payment systems which operate outside the regulatory framework; and the use of cryptocurrencies for money laundering and financing terrorist groups [6]. Meanwhile, the role of DLT has evolved from a \"digital currency ledger\" to a medium for realising transactions between unknown participants [7]. Further applications include disintermediated environments that enable trust-less payments [8] and decentralised and immutable storage [9]. DLT is used in a number of government applications. Examples include notary services for citizens [10], inventory management [11], patent [12] and energy trading [13], securing archives of public documents [14], B2G information sharing [15], and land registry [16]. Central banks across the globe, as part of public sector explorations of DLT, have been considering providing DLT-enabled digital currencies [17; 18; 19] directly to the general public through accounts held in their books [20] as a complement to fiat currency, which is currently offered via cash or through commercial banks. Recent research efforts around the globe lead by central banks [21; 22; 23; 24] are actively exploring the characteristics, design criteria, implications, and acceptance of central bank digital currencies, also known as CBDCs. Developments in DLT, particularly those related to expanding the functionality of smart contracts, accentuate the concept of 'programmable money' [24], which creates opportunities for fiscal policy implementation. Similarly, controlling spending on social benefits such as Universal Credit [25] can be provided in the form of special-purpose tokens which can be spent exclusively on particular classes of goods and services, e.g., food, rent, and medicine. A CBDC can operate as a public policy actuator with just-in-time targeted interventions in the event of financial or health crises with large economic impact. The advent of DLT and CBDC comes at a time when payments are undergoing radical changes on a global scale, triggered by events such as the implementation of Payment Services Directive 2 [26], open banking [27], the ISO 20022 electronic data interchange standard [28], the transformation of payment systems such as UK's New Payments Architecture (NPA) [29], and the transformation of cross-border payments via the introduction of SWIFT GPI [30].