Titan: Questions raised over sub safety

The co-founder of the firm that developed the Titan submersible has rejected claims that it cut corners, after five people died descending to the wreck of the Titanic. We hear from US sub safety expert William Kohnen.

Also in the programme: James Cameron pays tribute to Titan dead; and the British Nigerian chefs backed by Beyoncé.

(Photo: Undated handout photo issued by OceanGate Expeditions of their submersible vessel named Titan. Credit: OceanGate Expeditions/PA Wire)