Pakistan remained a colony of Britain along with several other independent countries of the current times which are India, Bangladesh etc.
These countries of the sub-continent gained independence in the year 1947 from British Raj. These countries were colonized by the Britain because it was the super power of that time. It colonized several other parts of the world also because of its powerful status.
It got numerous benefits by colonization of various areas of the world. The best advantage was access to the natural resources of these countries. Pakistan and these other parts of the world were at a strategic location and had abundance of natural resources. For example the area of Pakistan and India has immense production of wheat, cotton etc that served as a major raw material for industries in Britain.
This colonization gave Britain power on all the other countries of the world.