Short drama: Pinter's first, a telly production (7)
I believe the answer is:
playlet
'short drama' is the definition.
(I've seen this before)
'pinter's first a telly production' is the wordplay.
'first' indicates taking the first letters.
'production' indicates anagramming the letters.
The initial letter of 'pinter' is 'p'.
'a'+'telly'='atelly'
'atelly' anagrammed gives 'laylet'.
'p'+'laylet'='PLAYLET'
(Other definitions for playlet that I've seen before include "Small drama" , "Short dramatic piece" , "Sketch" , "Short drama" , "Little work" .)