| Navy | The Royal Navy |
| Type | Submarine |
| Class | U |
| Pennant | N 66 |
| Built by | Vickers Armstrong (Barrow-in-Furness, U.K.) |
| Ordered | |
| Laid down | 19 Feb, 1937 |
| Launched | 16 Feb, 1938 |
| Commissioned | 5 Oct, 1938 |
| Lost | 29 Apr, 1940 |
| Loss position | 55.13N, 01.19W (See a map) |
| History | At 1730 hours on 29 April 1940 HMS Unity (Lt. Francis John Brooks, RN) sailed from Blyth to patrol off Norway. The visibility was down to 300 yards as Unity moved out of the harbour in the main channel, where the Norwegian ship Atle Jarl was proceeding on her way from Scotland to the Tyne. A short while later visibility was down to 100 yards and neither vessel was aware of the other until the submarine spotted the ship at 50 yards and on a collision course. There was just time to shut the bulkhead doors and order the engines astern before the Atle Jarl smashed into the submarine. The order to abandon the submarine was given and Unity sank only five minutes after the collision in position 55º13'N, 01º19'W.
Commanding Officers: Lt. Francis John Brooks, RN |
| Noteable events involving Unity include: 5 Apr, 1940 |