| Name | First Aired | Runtime | Image | |
|---|---|---|---|---|
| S04E01 | Christmas |
December 28, 2017
BBC One
|
30 | |
| S04E02 | Episode 2 |
January 7, 2018
BBC One
|
30 | |
| S04E03 | Episode 3 |
January 14, 2018
BBC One
|
30 | |
| S04E04 | Episode 4 |
January 21, 2018
BBC One
|
30 | |
| S04E05 | Episode 5 |
January 28, 2018
BBC One
|
30 | |
| S04E06 | Episode 6 |
February 4, 2018
BBC One
|
30 | |
| S04E07 |
Episode 7
season finale
|
February 11, 2018
BBC One
|
30 |
No artwork of this type.
No artwork of this type.