Title: The Illusion of the Printing Press: What Really Happens to the Pound Under MMT

Introduction

Modern Monetary Theory (MMT) has moved from the academic fringe to the center of political debate. Proponents argue that a sovereign government issuing its own currency cannot go bankrupt and should prioritize full employment over deficit reduction. Critics contend that such a policy mix would trigger a currency crisis. But what would actually happen to the British pound if a government led by MMT principles took power? To answer this, we must look beyond political rhetoric and examine the mechanical realities of fiat currency, inflation, and central bank independence.

The Mechanics of a Floating Currency

The debate often begins with a misunderstanding of how money works. Under a floating exchange rate regime, a government does not need to "find" money to spend. It creates it. The constraint is not solvency but inflation. If the government spends too much relative to the economy’s productive capacity, prices rise.

For the pound, the immediate effect of an MMT-style government would not be an instant collapse. Instead, the currency would act as a pressure valve. As the government injected liquidity to fund large-scale public programs, the supply of pounds would increase. Basic economics dictates that, all else being equal, an increase in supply leads to a decrease in price. In the forex markets, this would manifest as a depreciation of the pound against other currencies.

The Inflationary Constraint

MMT advocates correctly note that taxes drive demand for the currency. However, they often underestimate the speed at which markets react to fiscal expansion. If the government attempted to fund a Green New Deal or a Job Guarantee scheme without corresponding taxation to withdraw excess demand, the result would be inflation.

Crucially, the UK is not a closed economy. It imports a significant portion of its food and energy. A depreciating pound makes these imports more expensive. This creates "imported inflation," which feeds directly into the Consumer Price Index (CPI). An MMT government would therefore face a dilemma: if it raises taxes to control inflation, it undermines the disposable income it sought to create. If it allows inflation to run, the purchasing power of the pound erodes, hurting the poorest in society the most.

Bond Markets and Interest Rates

The reaction of the bond market is the second major factor. MMT posits that a government can issue debt in its own currency and set interest rates independently of market forces. In practice, if investors fear that the government is debasing the currency to pay off debt, they will demand a higher yield to hold British gilts.

If the Bank of England (BoE) were forced to suppress these yields—by buying government debt directly—it would be engaging in what is known as "fiscal dominance." This erodes central bank independence. Markets would view the pound as a riskier asset, further driving down its value. A sharp depreciation could trigger a feedback loop: lower currency value leads to higher import prices, which leads to higher inflation, which leads to higher interest rate expectations, further damaging the currency.

The External Constraint

The UK runs a persistent current account deficit, meaning it imports more than it exports. This requires a steady inflow of foreign capital to finance the gap. If the pound weakens significantly due to fears of fiscal profligacy, foreign investors may hesitate to hold sterling assets. This could create a funding crisis, not because the government cannot print money, but because the private sector requires foreign currency to pay for imports.

In this scenario, the government would face a stark choice: allow the pound to float freely and accept the inflationary consequences, or introduce capital controls. Capital controls would restrict the movement of money across borders, a move that would likely be met with alarm by international investors and could isolate the UK financially.

Conclusion

An MMT government would not cause the pound to vanish overnight. The currency is backed by the productive capacity of the UK and its legal status as a medium of exchange. However, the pound would almost certainly depreciate. The severity of that depreciation depends entirely on how the government manages the inflation constraint.

If the government uses its fiscal space responsibly—taxing enough to offset spending and targeting genuine bottlenecks in the economy—the currency could stabilize. But if it ignores inflation and relies solely on the printing press, the pound would suffer. The real risk of MMT is not bankruptcy, but the erosion of purchasing power and the loss of central bank credibility. The pound would survive, but its value would be determined by the discipline of the government that issues it.