Film-makers have infiltrated the ocean with secret cameras to capture dolphin behaviour in the wild as it has never been seen before.

They enlisted a menagerie of creatures, such as a molluscs, sea turtle and squid, with hidden lenses to get up close and personal for a new BBC natural history programme.

The series director John Downer and producer Rob Pilley spoke to BBC Breakfast.

Dolphins - Spy in the Pod begins on January 2 on BBC One at 8pm.