Former Progressive Conservative Prime Minister Brian Mulroney says any politician who chooses to ignore climate change in their campaigning will "pay the price."

In an interview with Don Martin on CTV's Power Play, which aired Tuesday, Mulroney pointed out that when it comes to climate change, "the broad middle class in Canada will not accept indifference on this issue."

"[Canadians] want more than anything else, I think Don, to pass on…to their children and grandchildren, a pristine environment, and anybody that doesn't understand that or campaigns against it is going to pay the price," Mulroney said.

Pollsters have been echoing Mulroney's warning. A Sept. 9 poll conducted by Nanos Research found that just over 27 per cent of Canadians said the environment is the most likely issue to influence their vote – topping the list of their key concerns.

It's not an overly surprising stance for Mulroney, who in 2006 was crowned the "greenest prime minister" in Canadian history following a survey of environmental experts. His passage of the Environmental Protection Act and his fight against acid rain were key moves that saw the former prime minister land that prize.

In his interview with Martin, Mulroney went on to emphasize the achievements of another key green figure: Green Party Leader Elizabeth May.

"Elizabeth May worked for me in 1985 and 86, and she was responsible for a lot of good work…and I'm delighted that Elizabeth, who's an outstanding person, that she is bringing to public attention the calamitous effects of non-action in this area," he said, referring to climate change.

He said one doesn’t have to accept all May's ideas – or "those of the Green Party" – to see that Canadians will not settle for indifference on the issue.

Mulroney said People's Party Leader Maxime Bernier's stance on climate issues, which includes the belief that Canada is only liveable thanks to "natural climate change," will be a tough sell.

"I like Maxime, but he may – he's going to find it difficult to sell that idea anywhere in Canada," Mulroney said.

Voters will give their verdict on parties' environmental platforms – and other key issues – when they head to the polls in the federal election on Oct. 21.

Parties should stay the course on Quebec secularism bill: Mulroney

Mulroney also weighed in on another hot button issue: the controversial Quebec secularism bill, which bans religious symbols for teachers, police officers and other public servants in positions of authority.

He said the government should allow the ongoing court challenge of the bill to proceed – and could consider intervening at a later date.

"It'll eventually wind up in the Supreme Court of Canada. The government may wish to intervene at the Court of Appeal or at the Supreme Court level if they wish at the time, but for the moment I think they're following an acceptable path by allowing the courts to deal with it in an objective and fair manner," Mulroney said.

The case is moving on to the Quebec Court of Appeal after the Court agreed on Aug. 1 to revisit the issue. They have yet to announce when that challenge will take place.