### Clue: Secure, like boltholes for spies when hiding (2,4,2,6)
### Answer: AS SAFE AS HOUSES 
 ### Explanation: Definition: Secure
  AS(like, as used in a simile like this) + SAFE HOUSES(hiding places,boltholes for spies on the run) **containing**(…hiding) AS(as in "as and when").  A WIWD clue.