Senior ministers start to carp somewhat about Tyneside (7)
I believe the answer is:
cabinet
'senior ministers' is the definition.
(I've seen this before)
'start to carp somewhat about tyneside' is the wordplay.
'start to' indicates taking the first letters.
'somewhat' becomes 'abit' (a bit).
'about' indicates putting letters inside.
'tyneside' becomes 'ne' (region in North East of England).
The initial letter of 'carp' is 'c'.
'abit' going around 'ne' is 'abinet'.
'c'+'abinet'='CABINET'
(Other definitions for cabinet that I've seen before include "accommodating senior ministers" , "Collective noun for senior ministers" , "Piece of furniture for members of a government" , "meeting at Number Ten" , "Government committee" .)