It lies between Britain and Scandinavia (5,3)
I believe the answer is:
north sea
'it lies between britain and scandinavia' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for north sea that I've seen before include "Water beside UK" , "Oil producer" , "A great deal of water" , "Area of natural gas" , "Water between the UK and mainland Europe" .)