An inflatable octopus bigger than a double decker bus has risen from the murky depths of the Thames outside the Houses of Parliament - to demand a sea-change in the UK government’s approach to protecting the seas.

The 20-metre tall "octo-activist" is part of a Greenpeace protest action, after the environmental action group says the government pushed back ratifying a newly-signed global ocean treaty until after the next general election. The UK was one of the first governments to sign the high seas treaty at the United Nations General Assembly when it first opened for signatures in September.

Video: Greenpeace