Sensational start to London university -- and free (5)
I believe the answer is:
lurid
'sensational' is the definition.
('lurid' can be similar in meaning to 'sensational')
'start to london university and free' is the wordplay.
'start to' indicates taking the first letters.
'and' says to put letters next to each other.
'free' becomes 'rid' ('rid' can be a synonym of 'free').
The first letters of 'london university' is 'lu'.
'lu'+'rid'='LURID'
(Other definitions for lurid that I've seen before include "In shocking detail" , "Shockingly sensational" , "Sensational or dazzling" , "Melodramatic" , "Shocking; vivid in colour" .)