| Clue | Source | Date |
|---|---|---|
| Electric sirens or warning hooters | The Guardian Weekend | 25 Nov 2023 |
| Electric sirens or warning hooters (7) | ||
| . Monarch's careless with wayward son's noisy apparatus | ||
| Loud horns | The Telegraph Quick | 04 Nov 2020 |
| Electric horns or warning hooters | The Guardian Speedy | 09 Feb 2020 |
| Vintage auto horns | ||
| Hooters | The Telegraph Quick | 14 Jul 2017 |
| They may act as warnings | ||
| Horns | The Telegraph Quick | 30 Mar 2016 |
| "Ah-OO-gah!" horns | ||
| Submarine dive alarms | ||
| Old car horns | ||
| Electric horns | ||
| Loud auto horns | ||
| Auto horns. |