You Do Need power plug adapter while traveling from Western Sahara to Northern Ireland.

Here is Why You Need An Adapter

The outlet and plug type used in Northern Ireland is G and in Western Sahara are C and E. This is how they look like.

Western Sahara

In Western Sahara, outlets of type C and E are in use.

Type C

Type E

Northern Ireland

In Northern Ireland, outlets of type G are in use.

Type G