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

Here is Why You Need An Adapter

The outlet and plug type used in Sint Maarten are A and B 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

Sint Maarten

In Sint Maarten, outlets of type A and B are in use.

Type A

Type B