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

Yemen

In Yemen, outlets of type A, D and G are in use.

Type A

Type D

Type G

United Kingdom (UK)

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

Type G