As an empire, the decay of U.K. was inevitable since WW II. The war had defeated U.K. In many aspects even though as part of the Ally she won at the end. Two major consequences of the war basically prescribed the fate of British Empire in the coming century. One is that the colonialism was pronounced dead no matter how the colonial powers wanted to maintain it. Two is that the economy and the military power of U.K. was devastated to the point it was difficult to return to her pre-war status. The U.S. came out the strongest winner in manufacturing and military power benefiting from the war occurring outside of North America. Inevitably, the U.S. would lead the world to recovery with her Marshall Plan for Europe and a restoration plan for Japan. Strategically, the U.S. took the opportunity of constructing an anti-communism alliance countering the expansionism of the post-war Soviet Union with NATO (formed in 4-4-1949) established in Europe. In Asia, the U.S. was the occupier of Japan for seven years (1945-1952) restructuring Japan's political system and industrial base. The occupation ended in 1952 shortly after the San Francisco Peace Treaty was signed by 49 countries on September 8, 1951. The U.S. and Japan entered into a security sharing relationship which was later negotiated into a Mutual Alliance Treaty signed on January 19, 1960 in Washington DC, finally approved by the Japanese Diet despite of violent protests by the Japanese leftists.
The U.K. adopted the strategy to be the most intimate ally of the U.S. content with a follower position in the international arena as well as in the world economy. The U.S. was the world's strongest economy and military power and the U.K. was functioning under the superpower's wings to maintain her kingdom image and to sustain a struggling economy with world competition not only from European nations but also Asian countries. Due to population and resources disadvantage, the British aisles have difficulty keeping up with the world in hard goods manufacturing but to rely more on financial engineering and soft power. This situation does not provide an optimistic long term prospect for several reasons. One is that the U.S. (for different reasons from the U.K.) is gradually moving into the financial sphere becoming the dominant player often taking everyone's lunch. In addition, the developed nations in Europe and particularly late comers in Asia have all become strong competitors in the world economy. The rise of China was apparently gaining China enough influence on the world stage, hence, returning Hong Kong (HK) to China (1997) was inevitable no matter how unwilling the U.K. was to part with a money making HK. China's continued near double digit economic growth in GDP for next two decades have made China a strong competitor to all. This competition is threatening the economic dominance of the U.S., therefore, eventually leading into a trade war between the U.S. and China.
Into the twenty first century, the decline of the U.S. economic power has become obvious, finally evidenced by the global financial crisis triggered by the U.S. housing loan bubble in 2008. The crisis was saved by China by her buying U.S. treasury debt. As China has become the world number two economy (number one in terms of buying power), many country including U.K. must adjust their trade and economic development strategy. Facing this challenge, the U.K. is forced into a reactionary position with no clear long term policy. This can be seen from her relationship with China, the U.S. and EU. First, the U.K. wasn't sure how to maneuver in the EU system to maximize her economic gain, hence there was the Brexit issue which took a while to decide and still not resolved with a clean break with EU. The U.K. left the EU on January 31, 2020 with a deal called Withdrawal Agreement which covered 1) agreeing a transition period and how it could work, 2) How to prevent border check at Irish border and 3) U.K.'s financial settlement with EU. There is the 11 month transition period ending December 31, 2020 with a deadline of extending the transition already passed. The issues stuck at negotiation level include a trade deal, immigration rules, fishing access and security co-operation. If the transition period is passed without an accord, then tariffs and border checks will take place. What will happen remains to be seen, hence you may say that UK is in a yoyo state as far as exit from EU.
Towards China, the U.K. was perhaps even more uncertain. For a while, U.K. was extremely friendly towards China, very much eager to be her partner. She joined the Asian Infrastructure Investment Bank initiated by China early to support China's One Belt One Road initiative. However, when the U.S. anteed up her anti-China policy with trade war, technology sanction and military intervention in the South China Sea with an ambitious NATO-like alliance in mind for the Indo-Pacific region targeting China, the U.K. yoyoed. First, the U.K. and the U.S. took the same stand supporting HK protests which were turning into violence. That was a clear case of double standard, comparing the rationale and government measure in HK riots with those happening in the U.S. and U.K. Now, China has passed a national security law to protect HK, the riots are stopped. However, the U.K. announced a policy permitting British National Overseas (BNO) to apply visa to settle in UK with opportunity to apply for citizenship later. Obviously, this policy displeases China. UK Home Office estimates around 3M people with BNO status and some 500,000 could arrive in the first year as an extreme scenario, more likely 123,000 to 153,000 people would arrive in the UK in the first year, and between 258,000 and 322,400 over five years. U.K. expects a lot of them to be educated workers with wealth potentially paying taxes boosting the UK economy by 2.4B pounds. Judging the economic prospect of U.K versus China, this is absolutely a fantasy, a wishful thinking the best. Only those people with money acquired in shady manners would escape to UK, not workers, since the job opportunity is far better in HK and China.
As the world is watching, the U.S. is pulling all stops to resist Huawei company to dominate the 5G business, despite of the fact that Huawei leads with patents (3000 applications and 1200 granted, collecting $1.2B and paying $6M in licensing fees) in 5G technology and standards and business relations with 170 countries. On this matter, the U.K. is yoyoing again. First, she denied Huawei had any backdoor security exposure in its telecommunication equipment when the U.S. accused Huawei, then she joined the U.S. to forbid Huawei to bring its 5G technology into their domestic markets, eventually removing any existing Huawei equipment. This pattern of yoyoing, to some degree, reflects the U.K. government's inability to act independently from the U.S. We don't need to dwell on the false logic of the U.S. in adopting a self-inflicting policy to punish a civilian company, Huawei, but we must emphasize that the U.K. cannot afford to miss the 5G technology revolution (by yoyoing) which will bring electric car, AI-robotics and all sorts of Internet applications running at split second speed. Take financial application-transactions, China is already leading the world; adopting 5G a few years ahead of every one, one can imagine China's role in the financial world that the U.K. so depends on. A yoyoing UK will eventually be left bouncing on the side walk. As the editor in The Economist updated the article, A Ban on Huawei further worsen Britain's relations with China ( July, 11, 2020), to incorporate the announcement of Huawei's exclusion from 5G telecommunication network, many papers popped up: Banning Huawei, … likely worsen the deteriorating UK-China relation, London's Huawei decision 'turning point' for China-UK relation, Britain Fears Chinese Government Retaliation Over Huawei.... As British media are full of intelligent people, I expect someone will be honest enough to tell the UK politicians: a “yoyo' State or 'yoyo' China policy is not good for U.K. She must act as an independent nation for her own good.