In January Campbell joined the board of the Sea Shepherd Conservation Society, a group sometimes avoided even by Greenpeace. Over the summer Watson's vessel engaged in cat-and-mouse interference with Japan's Southern Ocean whaling fleet, employing stunts that included hurling rancid butter on to the deck of a Japanese whaler. But the whale kill was severely disrupted.

Campbell says he admires this sort of direct action, provided it can be done safely, but he never needed a conversion to the cause. His passion for whales goes back to 1970 when a 16-year-old Campbell discovered a tape of whale songs in the Brisbane Grammar library.

"It was quite captivating ? It's something that's been close to my heart all my life."

The next year he had his first sighting of a humpback off the Western Australia coast while sailing with his father. He was hooked, and became determined to see that whales were not.

Thanks to a history of cynicism around the Save the Whales slogan, there were some shaky moments inside a federal government not usually noted for an obsession with preservation.

At a Liberal Party reception in 2006, when Campbell thanked the British fisheries minister for helping to pull together a coalition of nations opposed to Japan at the International Whaling Commission, the old stereotypes were there. "There were a few giggles around the table," Campbell said.

It has been reported that John Howard became exasperated with Campbell's views on whaling and his supposedly "waffling" style. The former senator sees it differently.

"I got strong support, from the PM down. He said, 'Do what you've got to do'," Campbell said. "And I had strong support from [foreign minister Alexander] Downer. Save the Whales had become such a cliche the debate had to be re-engergised. A lot of very conservative people were supportive."

The then Liberal Party president Shane Stone was won over by Campbell's persistence when the two were seated together at a Parliament House dinner honouring the Queen's visit in 2002.

"He was listening to what I was saying and he offered to help with his international contacts ? and he bloody well did."

Partly due to Campbell's insistence, the Howard government became a visible leader of the international fight to curb Japan's exploitation of a moratorium loophole that allows "lethal research".

Campbell says Australia's campaign has lost momentum because it failed to press for a vote that would have embarrassed Japan at a meeting of the International Whaling Commission last June. Instead, the Rudd Government is pursuing reform of the commission, an arduous process that Japan and its international recruits are well equipped to resist. In the last few months Eritrea, Tanzania and the Republic of Congo have joined the commission as voting members, reportedly after talks in Tokyo that emphasised Japan's "sustainable whaling".

Campbell described the composition of the commission as "bullshit" and attacked the Rudd Government for what he sees as inaction. "At least when we were in government we called scientific whaling for what it was - a farce," he said.

However, the Environment Minister, Peter Garrett, says: "There was a wristband campaign ? but nothing of substance. For over two decades the debate over 'scientific' whaling has been gridlocked in claim and counter claim, and all the while the number of whales targeted by Japan in the Southern Ocean has increased - in particular, doubling between 2004-05 and 2005-06 under the watch of Senator Campbell."

Last October the Government appointed Sandy Hollway as its "whaling envoy", with a mission to persuade the Japanese to rethink the annual hunt and to convince other nations that whales can be studied without killing them. Garrett has announced funding for a non-lethal research program while the diplomatic offensive goes on.

But before flying to Japan last October, Hollway warned that expecting an end to the killing was "false hope". "I think we might be past the point where the definition of success is a complete halt," he said.

Ben Cubby is the Herald's environment reporter.