Appeal of Daily Mail's leader (5)
I believe the answer is:
charm
'appeal' is the definition.
('charm' can be a synonym of 'appeal')
'daily mail's leader' is the wordplay.
'daily' becomes 'char' (I've seen this before).
'leader' suggests taking the first letters.
The first letter of 'mails' is 'm'.
'char'+'m'='CHARM'
'of' acts as a link.
(Other definitions for charm that I've seen before include "Enchant" , "Entrance; amulet" , "Trinket on a bracelet" , "Power of fascination" , "Delight; magical object" .)