Filming, which commenced in early February 2020, was interrupted on March 17th due to the COVID-19 pandemic. Production resumed after five months, on August 14th 2020 and was completed in early September. Actress Rose Leslie, who was in the early stages of pregnancy when filming began, was eight months pregnant when it resumed.
There are 4 Vanguard class boats in the Royal Navy; Vanguard (S28), Victorious (S29), Vigilant (S30) and Vengeance (S31).
On Tuesday, 22nd March 2022, the British Broadcasting Corporation announced that they have commissioned a 6-episode second series of the drama with further details to be announced.
This is the second time actor Adam James (Prentice) has appeared in a submarine thriller with him also having starred in Hunter Killer (2018).
Rose Leslie (Longacre), Stephen Dillane (Shaw), Daniel Portman (Walsh), Sam Redford (Ingles) all starred in Game of Thrones (2011).