Police search for suspect in flowering garden close to Parliament (7)
I believe the answer is:
dragnet
'police search for suspect' is the definition.
(a dragnet is a police search)
'flowering garden close to parliament' is the wordplay.
'flowering' is an anagram indicator (letters develop or 'flower' into another form).
'close to' suggests the final letters (the close/ending of).
The last letter of 'parliament' is 't'.
'garden' is an anagram of 'dragne'.
'dragne'+'t'='DRAGNET'
'in' is the link.
(Other definitions for dragnet that I've seen before include "hunt for suspect" , "Intense police search for suspect" , "Granted, this may be an organised system of gathering in" , "Systematic search (for criminals)" , "Fisherman might have one" .)