### Clue: Conservative leader to propose VAT (4)
### Answer: CASK 
 ### Explanation: Initial letter(*leader*) of *Conservative* + ASK(*propose* in the form of a question, one form of which involves the bended knee).  Defn:  A large container.  Setter intended misdirection with the upper case letters, resulting in my trying to fit CESS (a tax) in.