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

Rwanda

In Rwanda, outlets of type C, E, F and G are in use.

Type C

Type E

Type F

Type G

United Kingdom (UK)

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

Type G