Russian labour camp (5)
I believe the answer is:
gulag
'russian labour camp' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for gulag that I've seen before include "where state's enemies were held" , "penal system" , "Soviet detention camp" , "Book by Solzhenitsyn 'The . . . . . Archipelago' about detention camps in USSR" , "in restraint here?" .)