Ten hours travelling in one direction (8)
I believe the answer is:
southern
'in one direction' is the definition.
'ten hours travelling' is the wordplay.
'travelling' is an anagram indicator.
'ten'+'hours'='tenhours'
'tenhours' is an anagram of 'SOUTHERN'.
(Other definitions for southern that I've seen before include "away from the north" , "From below the Mason-Dixon Line" , "Of Cork or Waterford, say" , "Antarctica is in this hemisphere" , "Towards the Antarctic" .)