1. Britain does not want to lose its monetary policy autonomy: if it joins the euro, Britain's interest rate will be dominated by the European Central Bank, which means that Britain will basically lose its monetary policy autonomy and lose its ability to expand or tighten monetary policy. During the economic recession, Britain can't enhance its competitiveness or reduce the pressure of foreign debt through currency depreciation/inflation.
2. British nationals are opposed to joining the euro zone: The first public opinion poll conducted after the official circulation of the euro zone shows that only 2 1% people think that Britain should join the euro zone, while 73% of the British people are opposed to joining, and the proportion of opponents is larger than any previous survey.
3. Currency status of the pound: The pound is a traditional common currency, the oldest currency and one of the top ten foreign exchange trading currencies in the world. And London has always been the largest financial center city in Europe and the second in the world. Obviously, joining the euro zone will affect Britain's monetary status in Europe and even the world.
4. Power distribution: The EU is a national alliance centered on France and Germany, and the power center is in France and Germany. Germany has technical strength, while France has financial status and international status. However, Britain's accession to the EU currency can not separate more benefits from France and Germany, and there are not many actual benefits.