Touch on an objection? (4)

I believe the answer is:

abut

'touch on' is the definition.
(to abut on something is to touch or neighbour it)

'an objection' is the wordplay.
'an' becomes 'a'.
'objection' becomes 'but' (as in 'no ifs, no buts').
'a'+'but'='ABUT'

(Other definitions for abut that I've seen before include "Join" , "Adjoin, press up against" , "Adjoin -- 19 (rev)" , "Be next door to" , "Touch (side of next building)" .)

I've seen this clue in The Times and The Telegraph.

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