In the case of the United Kingdom, setting a target inflation rate at 2.5% is equivalent to announcing a strong commitment to containing inflation and maintaining price stability.
In contrast, since the early 1980s when the effects of the Second Oil Shock waned in Japan, the average rate of CPI increase has been very low at around 1%, and was only 3% at the peak of the bubble period when the economy was overheated. In the case of Japan, prices have been extremely stable for nearly twenty years.