The government's Clean Air Act must be beefed up if the Tories hope to win over crucial middle class voters, former prime minister Brian Mulroney says.

In an interview with CBC News, Mulroney, who was recently awarded the title of the greenest prime minister in history, described the act as the beginning of a plan and said to capture the imagination of voters, it needs more work before the next election.

"And I think there is more work to be done on that, both substantively and 'presentationally', and my guess [is] that is where the government is heading," he said.

"It would be politically regrettable if they were not to do that because they would be ceding control of this major political issue to a political party - the Liberals - whose reputation, whose achievements have been absolutely mediocre."

Mulroney said that for middle class voters there isn't much in the way of policy that resonates, beyond tax cuts.

The one key exception, he said, is the environment.

"This resonates well with this highly independent voting block in Canada," he said. "And if you want their support, and you can't get elected very often without it, then you've got to be sensitive to questions on the environment."

He said the Tories need to claim the environment as their issue.

A recent CBC poll revealed that the environment is almost tied with health care as the No. 1 priority for Canadians.

The Conservatives have been hammered over their Clean Air Act and their insistence that they cannot meet the Kyoto targets of cutting greenhouse gas emissions.

Recently elected Liberal Leader Stéphane Dion has made the environment a key platform of his agenda.

Last April, Mulroney was honoured after being crowned the greenest PM in a survey by Corporate Knights magazine of high-profile environmentalists and others.

Along with bringing in the Environmental Protection Act, Mulroney successfully negotiated an acid rain treaty with the United States. He described the negotiations as a long and brutal fight, but it reminded him that the issue of the environment must "be a priority."

Copyright © 2006 CBC