The Conservative government's monetarist experiment began with the 1980 introduction of the Medium Term Financial Strategy (MTFS). This was a clear break from the post-war consensus. Instead of discretionary, short-term demand management, the MTFS set out a multi-year framework of declining targets for monetary growth and public borrowing. The primary goal was to anchor inflationary expectations by signalling the government's unwavering commitment to sound money. The initial and most prominent target was a broad measure of money supply, Sterling M3 (£M3).

The strategy's logic rested on the assumption of a stable relationship between the money supply, nominal income, and prices. By pre-committing to a path of decelerating monetary growth, the government aimed to reduce inflation without the need for detailed intervention in wage and price setting. It was an attempt to apply a clear, simple rule to macroeconomic policy, shifting the focus from managing unemployment to conquering inflation.

Targeting Sterling M3 proved notoriously difficult. The measure, which includes physical currency and a wide range of bank deposits, began to behave erratically almost as soon as it became the central policy target. The stable velocity of circulation, a theoretical cornerstone of monetarism, failed to materialise. Instead, as the government attempted to squeeze the money supply, the financial system innovated, altering the relationship between the monetary aggregate and economic activity. This phenomenon became a classic example of Goodhart's Law in action.

The government's attempts to control this ballooning aggregate led to a sharp rise in interest rates. The Minimum Lending Rate reached 17% in late 1979. This aggressive tightening had profound consequences, not for the money supply itself, but for the real economy via the exchange rate.

High interest rates, coupled with the UK's newfound status as a net oil exporter thanks to the North Sea, attracted huge inflows of speculative foreign capital. This caused a dramatic appreciation in the value of Pound Sterling. The pound's effective exchange rate index rose by over 20% between 1979 and 1981.

This overvaluation was disastrous for the UK's manufacturing base. British exports became prohibitively expensive on world markets, while imports became cheaper, gutting domestic producers. The result was a severe industrial contraction, with manufacturing output falling by around 15% and unemployment more than doubling to over 3 million by 1982. This was the 'shock therapy' in practice.

The 1981 Budget, delivered by Chancellor Sir Geoffrey Howe, remains one of the most controversial in modern British history. With the economy deep in recession and unemployment soaring, Keynesian orthodoxy dictated a significant fiscal stimulus. Instead, Howe did the opposite, introducing a fiercely deflationary package of tax increases and spending cuts designed to reduce borrowing.

The econometric significance of this budget cannot be overstated. It was a definitive rejection of counter-cyclical demand management. The government's priority was not short-term unemployment but long-term supply-side credibility. By tightening fiscal policy during a slump, the government aimed to convince financial markets of its absolute determination to control inflation. This event marked a de facto shift in policy focus away from the uncooperative £M3 figures and towards a more controllable metric: the Public Sector Borrowing Requirement (PSBR).

The 'shock' of the 1979-81 period did eventually bring down inflation, but at a huge cost to the country's industrial capacity. The experience demonstrated the immense difficulty of applying simple monetarist rules to a complex, open economy. The initial focus on £M3 was quietly abandoned in favour of a more eclectic approach, incorporating exchange rates and, most visibly, the PSBR as key indicators of the monetary stance.

Time to check your understanding of the early Thatcher-era economic policies.

Ultimately, the practical application of monetarism in the UK was a story of unintended consequences, forcing a pragmatic evolution of policy away from rigid targets towards a more discretionary framework.