2.2 Legal Basis for Sterlingisation
Is the continued use of sterling legally possible without a formal currency union?
The core question is legal and practical: can sterling continue to be used legally without a formal currency union? The short answer is yes. Unilateral use of sterling—commonly called sterlingisation—is legally possible and requires no agreement from the UK Government or the Bank of England. Scotland already uses sterling. Independence does not extinguish the right of people, businesses and institutions to continue using it. Successive UK governments have ruled out a formal currency union, and this framework does not seek one.
Confusion between two different arrangements drives much of the public argument. A formal currency union would mean shared monetary institutions, shared policy and typically formal lender-of-last-resort arrangements. That requires agreement; it has been refused; it is not pursued here. Sterlingisation means continued ordinary use of sterling for wages, prices, contracts, savings and payments without sharing monetary sovereignty. That does not require UK permission. The legal and practical basis of the second arrangement is the subject of this section. The constraints of sterlingisation—no independent interest-rate policy, no automatic Bank of England backstop—remain real and are managed elsewhere in the monetary framework. They do not make unilateral use illegal or impossible.
The distinction matters because a narrative that “Scotland cannot keep the pound without permission” conflates the refusal of a formal union with a supposed ban on ordinary use. That narrative is false as a legal claim and harmful as a confidence claim. Continuity of the unit of account supports continuity of contracts, mortgages, savings, pensions and day-to-day transactions at the moment of maximum institutional stress. The 18–24 month working timeline, the negotiation red line on sterling, and the supporting institutions of fiscal rules, a Scottish Central Bank focused on stability, bank regulation, deposit protection and reserves all presuppose that the legal basis for continued use is secure. Precision about what the law permits, what it does not require, and what the regime's constraints actually are is therefore essential to credibility with households, businesses, markets and counterparties.
Current Position and Legal/Institutional Baseline
Sterling is already the unit of account, medium of exchange, and store of value for the Scottish economy in ordinary use. Scottish wages are paid in sterling, prices are set in sterling, mortgages and bank accounts are denominated in sterling, and the overwhelming majority of contracts are written in sterling. The Bank of England issues the currency and sets monetary policy for the sterling area as a whole. There is no separate Scottish currency in general circulation as legal tender and no separate Scottish monetary authority. The existing legal and institutional baseline is complete integration into the sterling system for private and most public transactions.
In a market economy, currency use is driven primarily by acceptance, not by a requirement for formal authorisation from the issuing authority for every private transaction. Individuals and firms are free to denominate obligations, make payments and hold balances in a widely accepted convertible currency. Governments cannot easily prevent the use of a currency already embedded in wages, prices, contracts, and payment systems. The Acts of Union and the subsequent constitutional development of the United Kingdom did not create a unique legal barrier that would extinguish the ability to use sterling upon a change in constitutional status. Independence ends the application of UK constitutional and monetary arrangements to Scotland as a matter of sovereignty; it does not convert or invalidate existing private sterling obligations or prevent their continuation.
The baseline after a lawful Yes vote is therefore a choice between continued unilateral use of sterling under a domestic institutional framework designed for stability, or the immediate launch of a new Scottish currency. Formal currency union—shared institutions, shared policy and formal lender-of-last-resort arrangements—has been ruled out by successive UK governments and is not sought. Treating that refusal as if it were a ban on the use of sterling confuses two distinct questions. This framework keeps them separate. The legal permissibility of unilateral use underpins the operational and institutional design of sterlingisation.
Mechanism and Delivery
The mechanism is the ordinary private and commercial use of a fully convertible currency that is already the unit of account for the Scottish economy, reinforced by continuity of contract under Scots law and, if desired, by express recognition in the interim constitution or related legislation. Individuals, firms, and public bodies in Scotland need no permission from the UK Government or the Bank of England to continue paying wages, setting prices, performing contracts, or holding savings in sterling. Independence does not automatically convert or invalidate those arrangements. Continuity of contract—already a core principle of this framework—means existing sterling obligations remain sterling obligations. Constitutional change does not force conversion.
The Scottish Parliament could, if it wished, legislate to recognise sterling as legal tender for certain purposes, or to provide that public obligations and payments are denominated in sterling. Even that step is not required for people and businesses to continue using it. Sterlingisation is therefore a practical continuation of the existing monetary reality, not the creation of a new legal privilege the UK must grant. The independence settlement and the interim constitution would confirm continuity of existing obligations in their existing unit of account. Scots law, which continues without interruption, supplies the legal foundation for the enforceability of those obligations.
Technical cooperation on payment systems, clearing and information-sharing would still be desirable and would be sought on a practical basis. Such cooperation is distinct from a formal currency union. If cooperation is limited, the cost falls on domestic payment-system design, correspondent arrangements and operational resilience—not on the legal ability of the economy to continue using sterling. The UK Government and the Bank of England cannot prevent the use of sterling in Scotland any more than they can prevent its use by individuals or firms elsewhere in the world. They can refuse to enter a formal currency union or to extend lender-of-last-resort facilities. That refusal is already factored into this position. It does not make sterlingisation illegal or impractical.
Continuity Design
Continuity of the unit of account is a design requirement that protects continuity of wages, prices, savings, mortgages, contracts and pensions. Existing financial contracts denominated in sterling remain enforceable under continuing Scots law without conversion or renegotiation. Household balance sheets face no forced currency shock. Businesses that price and invoice in sterling for the rest-of-UK market face no new transaction costs or exchange-rate exposure on that dominant trade. Payment systems that already operate in sterling continue. Accrued pension rights denominated in sterling continue without currency conversion issues. The default is continuity of the unit in which ordinary economic life is conducted.
The legal basis for that continuity is the combination of market acceptance of sterling, the continuity of Scots law and of existing contractual obligations, and the absence of any legal requirement for formal authorisation from the issuing authority for private use. Express confirmation in the independence settlement and interim constitution would remove any residual ambiguity. Continuity of the currency therefore aligns with continuity of law, contracts, Parliament, Government and rights. It reduces one of the most immediate sources of anxiety for households and firms at the moment of constitutional change. Any later move to a Scottish currency would be a managed change under pre-published tests, not an emergency response forced by a supposed legal barrier to sterling use.
Constraints and Trade-offs
Legal constraints
There is no legal barrier to the continued use of sterling in an independent Scotland. The legal constraint is limited to the domestic legislation required to establish the supporting institutions—Scottish Central Bank, fiscal rules, deposit protection, bank regulation—and to any residual statutory references that assume continuing UK monetary arrangements. Scottish legislation can address those references. Formal currency union would require agreement and has been refused; unilateral use does not. The legal constraint is therefore the need for clear domestic foundations for the stability framework, not any prohibition on using the currency itself.
Fiscal constraints
Establishing the legal basis of sterlingisation has negligible direct cost. The fiscal burden of the sterlingisation regime is the cost of the institutions and buffers that make it stable—central bank, deposit scheme backstop design, reserves—already signalled in the fiscal and monetary framework. Those costs are real; they are not a licence fee payable to the UK for using sterling. The opening fiscal deficit remains the central fiscal challenge. Sterlingisation does not solve it and does not pretend to. It avoids adding a monetary shock on top of it. The fiscal rules become more important under sterlingisation, not less, because monetary policy is external.
Operational constraints
Operational delivery of continued use requires that payment systems continue to function in sterling, that banks can clear and settle, and that public confidence in the unit's continuity is maintained. Technical cooperation on payment infrastructure would improve operational resilience; if limited, higher domestic capacity and correspondent arrangements are required. The operational constraint is ensuring continuity of payment and settlement systems while the supporting institutions are stood up. Early clarity that sterling continues, continuity of contract, and visible deposit protection are the mitigations. The unit's legality does not solve operational continuity; institutional design does.
Political constraints
Political pressure may arise from the persistent narrative that Scotland cannot keep the pound without UK permission, or from demands for an immediate Scottish currency framed as the only truly independent option. The political constraint is the need to maintain the distinction between formal currency union and unilateral use, to avoid deliberate or inadvertent conflation. The response is that the distinction is legal and practical: union requires agreement and has been refused; use does not require agreement and describes existing behaviour. Credibility depends on closing the gap between the false legal claim and the real operational and institutional tasks of making sterlingisation stable.
Time constraints
The legal basis for continued use requires no extended implementation period beyond confirming continuity of contract and preparing any express recognition in the interim constitution or related legislation. That preparation sits inside the 18–24 month working timeline. The time constraint is therefore modest for the legal basis itself and more significant for the operational and institutional framework that surrounds it. Early public clarity that sterling continues is itself a time-sensitive confidence measure. Competence in the supporting arrangements takes priority over symbolic debate about a legal barrier that does not exist.
Consistency with the Wider Framework
The legal basis for sterlingisation underpins the choice of sterling as primary currency, the negotiation red line on sterling continuity, continuity of contracts and pensions, and the constrained mandates of the Scottish Central Bank and lender-of-last-resort arrangements. It aligns with the constitutional continuity sections: existing obligations remain in force in their existing unit of account under continuing Scots law. There is no tension with fiscal rules; under sterlingisation, those rules are more important, not less, because monetary policy is external. There is no tension with the continuity of Parliament, Government, rights or the courts: the same continuity-first logic applies to the unit of account as to the legal and institutional order.
The distinction between formal currency union and unilateral use underpins the rest of the monetary framework. Formal union is unavailable and not sought. Unilateral use is legally possible and is chosen for the transition and early years. The regime's constraints—no independent interest-rate policy, no automatic Bank of England backstop—are acknowledged and managed through domestic institutions. The conditional path to a future Scottish currency remains open, subject to strict tests. The legal basis section closes the false claim that permission is required and thereby clears the ground for the operational and institutional work that actually determines stability.
Hardest Critiques and Direct Responses
Feasibility
The hardest practical critique is that Scotland cannot “keep the pound” without UK permission, or that unilateral use is inherently unstable or impractical. The response is direct. Unilateral use of sterling is legally possible and already describes ordinary private behaviour. Formal currency union is not required and is not sought. Stability under sterlingisation depends on fiscal rules, bank regulation, deposit protection and reserves—which this framework treats as mandatory accompanying policy. The legal basis is highly feasible. The regime's feasibility as a stable monetary arrangement depends on delivering the supporting institutions. The critique that conflates refusing a union with a ban on use is not a valid legal claim. The critique that sterlingisation is unstable by definition ignores the institutional design that addresses the real constraints.
Cost and fiscal burden
Critics will argue that the costs of the supporting institutions are a hidden price of “keeping the pound.” The response is that those costs are the price of stability under a constrained regime, not a licence fee for using sterling. Establishing the legal basis itself has negligible direct cost. The fiscal burden of the central bank, deposit protection design and reserves is real and is signalled in the fiscal and monetary framework. It is smaller and more controllable than the costs of a poorly prepared new currency at independence. Sterlingisation does not solve the opening fiscal deficit; it avoids compounding it with a monetary shock.
Dependence on agreement
Dependence on UK agreement for the legal basis of unilateral use is nil. Dependence on technical cooperation for payment systems is real but limited; if cooperation is limited, the cost falls on domestic design and correspondent arrangements. Dependence on Bank of England lender-of-last-resort facilities is not assumed and is not sought as a right. The response is that the legal ability to use sterling does not depend on UK permission, that cooperation is desirable for infrastructure, and that underwriting is not assumed. An adversarial UK posture cannot outlaw sterling in Scottish shops and contracts; it can refuse institutional sharing that was not sought in the first place.
Transition risk
Transition risk lies in confidence and liquidity, not in the legality of the unit of account. A narrative that “Scotland cannot use the pound without permission” is false as a legal claim and harmful as a confidence claim. Mitigation includes an early, clear public statement that sterling continues, continuity of contract under Scots law, and visible deposit protection and prudential standards. The legal basis section exists partly to close the confidence gap created by the false narrative. Operational and institutional readiness remain the ongoing tasks; legality is the starting point.
Alternatives (status quo and previous proposals)
Formal currency union is unavailable and not sought; it would share monetary sovereignty in ways inconsistent with the wider independence prospectus. Immediately introducing a new Scottish currency is legally possible but operationally riskier at the moment of independence and is deferred until tests are met. Claiming that UK refusal of a union blocks sterling use conflates union with use and is rejected as a matter of law and practice. The status quo of sterling use inside the United Kingdom ends with independence in its current institutional form; the framework replaces it with unilateral sterlingisation under a domestic stability framework. This prospectus deliberately clarifies previous material that left the legal basis ambiguous or treated formal union as the only alternative.
Political and public credibility
The claim most likely to be called unrealistic is that Scotland can “keep the pound” as if nothing had changed, or that the Bank of England must support a sterlingised Scotland. The precise answer is that private and ordinary public use of sterling can continue without UK permission; formal institutional support from the Bank of England is not automatic or assumed; stability is a domestic policy product under constraint. This section establishes legality and practical possibility. It does not establish a right to UK monetary underwriting. Credibility depends on maintaining the distinction between union and use, on early clarity that sterling continues, and on honest acknowledgement of the constraints that the supporting institutions must manage. A strategy that promised unconstrained access to Bank of England facilities or that treated the legal basis as dependent on UK permission would forfeit that credibility.
Position Summarised
Continued use of sterling is legally possible without any agreement from the UK Government or the Bank of England. Scotland already uses sterling; independence does not remove that ability. A formal currency union is neither available nor sought. Sterlingisation is a unilateral, practical arrangement with international precedents. It provides continuity for wages, prices, contracts and savings while the new state’s institutions and fiscal credibility are established. The constraints—no independent monetary policy, no automatic lender of last resort—are real and are addressed elsewhere in the monetary framework. They do not undermine the choice's basic legal and practical feasibility. Permission is not required for use; cooperation is desirable for infrastructure; underwriting is not assumed. Continuity of contract under continuing Scots law reinforces the result: existing sterling obligations remain sterling obligations. The legal basis is the starting point. Operational stability is the ongoing task.
Conclusion
Sterlingisation rests on a simple distinction. Formal currency union requires agreement and has been refused. Unilateral use of sterling requires no such agreement and describes the monetary behaviour Scotland already practices. Independence does not extinguish that behaviour. Contracts, wages and prices can remain in sterling; continuity of contract reinforces that result. The UK and the Bank of England can refuse a union and refuse automatic last-resort lending. They cannot, as a matter of law, prohibit the ordinary use of sterling in an independent Scotland. This framework accepts the refusal of a union, does not seek one, and builds domestic institutions for stability under constraint. Legal basis is the starting point. Operational stability is the ongoing task. The following sections take up that task: the role and mandate of the Scottish Central Bank, fiscal rules under external monetary policy, deposit protection, reserves, and the conditional path to a possible future Scottish currency. Continuity of the unit of account is the monetary counterpart of continuity of law, Parliament, pensions and contracts. Taken together, they define a transition that prioritises the stability of ordinary economic life over symbolic change on day one.
Series Footer
This analysis forms part of People’s Future Scotland: The Independence Debate, a series examining the practical, legal and institutional questions that would arise in any move to independence. Each section is designed to withstand scrutiny by setting out mechanisms, constraints and continuity requirements with equal clarity. The series proceeds from the premise that a decision of this magnitude requires a process and a prospectus that both supporters and opponents can recognise as serious.
