A long summer of Tory controversies, from the Guergis affair to scrapping the mandatory long-form census, has eroded Conservative support and left them tied with the Liberals, according to a new poll.

The latest Nanos Research survey, conducted for CTV and The Globe and Mail, has the Conservatives and Liberals at 33 per cent support.

"It's kind of like a knife-fight in a telephone booth," pollster Nik Nanos told CTV News Channel's Power Play. "Except in this particular case, I think the Conservatives are stabbing themselves, not the Liberals."

Support for the Conservatives sank a modest two percentage-points from a poll conducted at the start of summer. Meanwhile, the Liberals gained three percentage points.

But Nanos said the tie has more to do with political mistakes made by the Conservatives than Liberal successes -- namely, Michael Ignatieff's cross-country bus tour.

"This is more a result of an accumulation of problems for the Conservatives, like the census, Afghan detainees, the Guergis affair," said Nanos.

"The tight race is not a result of what the Liberals have done to move the numbers, it's what the Conservatives have done to depress their support."

When those surveyed were asked three leadership questions -- which leader they trusted more, which had a better vision for Canada and which was more competent -- Harper beat Ignatieff with a composite score of 83. The Liberal leader scored 39, while NDP Leader Jack Layton got 44.

But the NDP is also having a difficult time. The poll suggests that because of divisions within their caucus over the long-gun registry issue, support has fallen from 21 per cent to 16 per cent.

While the Liberals want to save the registry and will vote against an upcoming private member's bill to scrap it, NDP Leader Jack Layton says he prefers to seek a compromise.

New Democrats will be able to vote independently on the bill, and some have suggested they will support the Conservatives to kill the registry.

"The long-gun registry is political poison for the NDP," said Nanos. "Our polling indicates that urban NDP voters are very dismayed with the perception of division within the New Democrats."

Technical notes

• Interviews were conducted between August 28 and September 3
• Findings were based on 1,014 telephone surveys of voting-age Canadians.
• The poll is considered accurate to within 3.1 percentage points, 19 times out of 20