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

Laos

In Laos, outlets of type A, B, C, E and F are in use.

Type A

Type B

Type C

Type E

Type F

United Kingdom (UK)

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

Type G