You Do Need power plug adapter while traveling from Zambia 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 Zambia are C, D and G. This is how they look like.

Zambia

In Zambia, outlets of type C, D and G are in use.

Type C

Type D

Type G

United Kingdom (UK)

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

Type G