You Do Need power plug adapter while traveling from Great Britain to Niger.

Here is Why You Need An Adapter

The outlet and plug type used in Niger are C, D, E and F and in Great Britain is G. This is how they look like.

Great Britain

In Great Britain, outlets of type G are in use.

Type G

Niger

In Niger, outlets of type C, D, E and F are in use.

Type C

Type D

Type E

Type F