Produce social security cheque sent back in haste regularly by Earl (9)
I believe the answer is:
originate
'produce social security' is the definition.
'originate' can be an answer for 'produce' (thesaurus). I am unsure of the 'social security' bit.
'cheque sent back in haste regularly by earl' is the wordplay.
'cheque' becomes 'giro' (giro cheque is a kind of cheque).
'sent back' says the letters should be written backwards.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'by' is a charade indicator (letters next to each other).
'earl' becomes 'e'.
The alternate letters of 'haste' are 'at'.
'giro' backwards is 'orig'.
'orig'+'in'+'at'+'e'='ORIGINATE'
Can you help me to learn more?
(Other definitions for originate that I've seen before include "Create, initiate" , "Stem" , "pioneer" , "Cause to begin, be the first" , "Bring into existence" .)