The inspiration for London's blue whale

The BBC's Horizon programme has filmed the tagging of blue whales in the Pacific.

Richard Sabin from London's Natural History Museum joined John Calambokidis from the Cascadia Research Group to witness how the tracking devices are attached.

Richard was looking for inspiration as he sought to remodel the museum's front entrance to showcase a blue whale skeleton.

The Horizon documentary, narrated by Sir David Attenborough, goes out on BBC Two at 21:00 BST on Thursday, 13 July. It is then repeated on the iPlayer.