Why did Britain keep only one island when it was colonized all over the world?

Are you asking about the Malvinas Islands? Because most of the residents on the island are descendants of Britain, they want to be ruled by Britain, but they don't want to be a minority in Argentina. Britain is responsible to its people, and some of them will not give up this small archipelago. In addition, owning islands means that they can own a large area of water around them. The Persian Gulf, the North Sea oil field and the South China Sea oil field in China have also confirmed that the ocean may have a lot of resources. Anyway, Albania is not strong, the navy is inferior to Britain, and the local residents are British and will not rebel. Britain will naturally defend this place.

Other colonies are relatively complex, including British immigrants and aborigines, and have a strong sense of independence. Britain can't completely control them, it can only make them independent. For example, the United States is independent, surpassing its home country to become the strongest in the world. India's indigenous population is too large to be completely controlled. These former colonies were only ruled by Britain and were actually independent. Britain can't and can't keep these places any longer.