After little time, one devising plan for old politician (8)
I believe the answer is:
thatcher
'one devising plan for old politician' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'after little time' is the wordplay.
I cannot quite understand how this works, but
'time' could be 't' and 't' is present in the answer.
The remaining letters 'hatcher' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for thatcher that I've seen before include "Worker on ladder" , "Roof-working prime minister" , "Prime minister as roof-worker" , "Member of 7 [ORDER OF MERIT]" , "Baroness --, former PM" .)