Related Clues:
- Highest classified (information)
- Secret - soldier
- Highly classified
- Not open to scrutiny
- Highly confidential
- Very hush-hush
- Of the highest security classification
- Most confidential
- (Of information) strictly not for public consumption
- Keep it under your hat!
- Erect post (anag)
- Concealed after upturned pot hides mole's adventures
- Dossier stamp
- Secret — soldier
- Army recruit