Environmental activists said Mr Bloom should resign
A Yorkshire MEP has been urged to resign after praising the French secret service for sinking the Greenpeace ship Rainbow Warrior in 1985.
The vessel was blown up in New Zealand en-route to a French nuclear testing site. One man died in the explosion.
UKIP MEP Godfrey Bloom was filmed at last year's climate change summit in Copenhagen in front of the current Rainbow Warrior.
He says: "Well done the French for sinking one of these things."
Martin Deane, of the Yorkshire & Humber Green Party, said: "I find his comments disturbing.
"There will be lots of Greens and sympathisers across the country who find it scandalous and outrageous.
Mr Bloom filmed his comments in front of the current Rainbow Warrior
"He should resign.
"It shouldn't be the case that these outrageous statements go unchallenged."
The video was uploaded to Mr Bloom's YouTube channel GoddersVision, but was later removed.
Mr Bloom would not be interviewed by BBC News on Wednesday, but directed reporters to another video on his website in which he says: "When I was in Copenhagen I made the remark that it might not have been a bad thing that the French actually sank the Greenpeace boat.
"But the point I was really making is that it has been the green movement over the last 30 years which has called the shots.
"Biofuels, and all that came with the green lobby, have been a disaster for the world. None of it actually works."
Mr Bloom's opponents are now seeking legal advice to ascertain whether his comments about the sinking of the Rainbow warrior breached anti-terror laws.
Bill Waddington, of Hull law firm Williamsons Solicitors, told BBC News: "The content of what he appears to have said seems to glorify what we now know was an act of state-sponsored terrorism, effectively, one for which the French government subsequently apologised."
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