This paper makes three contributions. First we present a technique by which the monetary transmission mechanism of Germany, France, the UK and the Eurozone can be decomposed into its component cycles, compared across economies and across time. As a result, we found that the individual data generating processes have varied over time. Second we show that Germany has now converged on the rest of Europe and not vice versa, although Germany had dominated monetary policy making in Europe for many years. Third, we show that the UK as an outsider has behaved like a peripheral EMU country, even when EMU was not in place. In other words, the transmission mechanisms of Germany and the UK were fundamentally different. Hence, when that German monetary policy dominated Europe in a way that was not in line with the rest of Europe, never mind the UK, it is no surprise that the UK eventually left the ERM (1992). The current financial crisis may enforce the trend of convergence of the transmission mechanism. But there have been signs of a divergence between core and periphery, to some extent involving the UK, so this general convergence, as opposed to tighter convergence in the core, may not last.