The Tory MP running the party's by-election campaign in Corby has been secretly filmed apparently encouraging a rival to stand in the contest.
Chris Heaton-Harris was the subject of a sting by Greenpeace, who recorded him admitting he had wanted the anti-wind farm independent James Delingpole to join the race.
He said Mr Delingpole, a Daily Telegraph journalist and climate change sceptic, had put his name forward as part of a "plan" to "cause some hassle", according to the footage.
"Please don't tell anybody ever," he begged, believing he was speaking to the representative of a fictional lobbying group called Windefensible.
He was actually talking to undercover film-maker Chris Atkins, who made contact with him at the Tory Party conference last month.
The sting is embarrassing for the Tories, who are set to lose the by-election and are already at loggerheads with their Lib Dem coalition partners over energy policy.
In the film, Mr Heaton-Harris, said: "There's a bit of strategy behind what's going on. I'm running the Corby by-election for the Tories... and Delingpole, who is my constituent, and a very good friend... put his head above the parapet but won't put his deposit down... It's just part of the plan."
There are coalition tensions over wind farm policy
In another section that is only partly audible, the MP for Daventry appears to admit that he "suggested" the move to his friend Mr Delingpole, conceding this was "awkward".
"Please don't tell anybody ever. But he will not be putting his deposit down. He just did it because it's a long campaign, it's six weeks to cause some hassle and get... people talking," he said.
Asked if he was trying to put the anti-wind farm campaign on the agenda, he replied: "Exactly. And it will go through way past the Corby by-election stuff. I'm trying to write it into the DNA of the Tory party."
Mr Delingpole did later pull out of the race, the day after the Tory Energy Minister John Hayes controversially declared "enough is enough" about the spread of wind farms.
Mr Atkins met Mr Heaton-Harris a second time, on that same day, according to The Guardian.
The MP confirmed Mr Delingpole was pulling out of the election - calling the timing "contrived" - and said he would now write in support of the Tories in The Telegraph.
Just 24 hours later, he did exactly that, praising Mr Hayes' comments. Mr Heaton-Harris said it would be a "nice piece for the boss to see".
After the sting was revealed, the MP denied supporting Mr Delingpole's candidacy because pulling out before submitting a deposit means he was never technically a runner.
"There was no conspiracy or 'conspiring with an opposition candidate'," he said.
James Delingpole praised comments by Energy Minister John Hayes
He later issued another statement on his website, saying: "The quotes attributed to me range from factually correct statements to me bragging about things beyond my control, which has so often before been the failing of politicians.
"The implication that I choreographed any sort of 'secret plan' is simply not the case and I apologise if that is the impression given.
"It can hardly be said that my wanting to 'put this on the agenda' is new. I have spent years fighting onshore wind, getting over 100 MPs to sign a letter to the Prime Minister, securing debates and raising questions in Parliament and touring the country speaking to anti-wind groups.
"It is a subject I am passionate about and will continue to work on until communities across my constituency, Northamptonshire and the country have the protection they deserve."
Liberal Democrat deputy leader Simon Hughes said: "Some Conservatives are clearly so hell-bent on disrupting the coalition's green agenda that they're prepared to stab their own candidates in the back to do it.
"The coalition's position on wind farms and green energy will not change because the Liberal Democrats will not let it. The Conservatives should be in no doubt: we will hold them to their promises on the environment."
Home Secretary Theresa May, campaigning in Corby on Thursday, said: "Chris has made clear - and I am saying today - that he has been guilty of some silly bragging.
"He's been a good campaign manager. He's been out campaigning hard, and will be campaigning hard today and tomorrow."
But Michael Dugher MP, Labour's shadow minister without portfolio, described the affair as "astonishing" and said: "This is yet more evidence of the Conservative Party in chaos."
The Corby contest was sparked when Tory Louise Mensch quit her job to move to the US with her family. Labour are expected to win the by-election comfortably.