| Clue | Source | Date |
|---|---|---|
| Can't be subjected to a charge (12) | ||
| "Rebellion must have an ____ base, something guarded not merely from attack, but from the fear of it" (TE Lawrence) | The Times Specialist Sunday | 27 Oct 2024 |
| Impossible to be beaten | Mirror Tea Time | 16 Sep 2024 |
| Impregnable (12) | ||
| Impregnable base in USA, all newly set out | The Times Cryptic | 13 Apr 2022 |
| Girl's description of operational ship impervious to attack | ||
| Invincible organisation with a small crew is competent | Irish Times Crosaire | 15 Feb 2018 |