You Do Need power plug adapter while traveling from Afghanistan to United Kingdom (UK).

Here is Why You Need An Adapter

The outlet and plug type used in United Kingdom (UK) is G and in Afghanistan are C and F. This is how they look like.

Afghanistan

In Afghanistan, outlets of type C and F are in use.

Type C

Type F

United Kingdom (UK)

In United Kingdom (UK), outlets of type G are in use.

Type G