Labour has a 41% to 32% overall lead in Lord Ashcroft's latest mega opinion poll of more than 8,000 voters but David Cameron has a 48% to 40% lead over Ed Miliband when the respondents were asked who would make the best PM.

Those are the headline findings of a poll rich in detail. Entitled Project Red Alert, Lord Ashcroft writes about the strategic dilemma facing Ed Miliband on today's ConservativeHome comment pages: "He can either make clear to his supporters that there will be no return to the days of lavish spending, or he can fight an election knowing that most voters do not believe Labour have learned their lessons, and that many of his potential voters fear Labour would once again borrow and spend more than the country can afford."

But there is also plenty for the Tories to benefit from in this huge survey. Over on Leftwatch I've listed five big weak points in Labour's electoral position.

Here are 10 other key findings from the report:

1. Voters prefer the idea of red-led government to blue-led government … 56% would like to see Labour in power in some form and only 44% would like to see the Conservatives in office (on their own or in coalition with the Lib Dems).

2. [That is] despite the fact that more than half of voters say Labour can't be trusted with power again! More than half of voters – 52% – surveyed by Lord Ashcroft say: "Labour have not yet learned the right lessons from what went wrong during their time in government, and cannot yet be trusted to run the country again," while 48% think Labour have learnt the right lessons from their defeat (35%) or didn't have any lessons to learn (13%).

3. Cameron is still ahead on prime ministerial qualities … On six measures of prime ministerial qualities (representing Britain in international negotiations, making unpopular but necessary decisions, clarity of agenda, ability to lead a team and overall skills), Cameron beats Ed Miliband. The Labour leader has a 63% to 37% advantage in the one area of understanding ordinary people.

4. Overall, Ed Miliband remains a substantial drag on his party's fortunes: 40% feel more favourable to Labour than to Ed Miliband and just 9% feel more favourable to Ed Miliband than to Labour.

5. But the Labour brand is stronger than the Tory brand: 49% think Labour is the party that most wants to help ordinary people get on in life compared to just 24% thinking the same of the Conservatives (or the Liberal Democrats); 39% think the Labour party is "on the side of ordinary people" compared to 27% who think that of the Conservative party. On only one quality are the Conservatives ahead – "willing to take tough decisions for the long term" – by 48% to 28%.

6. Tories are still more trusted on the economy but only narrowly: by 53% to 47% Cameron and Osborne are preferred over Miliband and Balls "to manage the economy in the best interests of Britain".

7. The two parties appear to be level-pegging when it comes to competence … 30% of voters see Labour as "competent and capable" – exactly the same as for the Conservatives.

8. But voters think nearly everything would have been worse if Labour had been in power. Asked if they thought key areas of national performance would have been better or worse if Labour had been in power over recent years, rather than the coalition, voters think things would have been worse in most key areas of public policy:

• Britain's overall level of debt: -32% (49% of voters think the debt level would have been worse and only 17% think it would have been better if Labour had been in charge).

• The problem of some people living on benefits when they are able to work: -30% (47% over 17%).

• Managing immigration into Britain: -25% (43% over 18%).

• Overall state of economy: -19% (45% over 26%).

• Britain's overall reputation in the world: -17% (37% over 20%).

• The crime rate: -11% (29% over 18%).

• Unemployment rate: -4% (35% over 31%).

• Public services such as the NHS: +12% (26% over 38%).

• Impact of public spending cuts: +14% (28% over 42%).

9. The Liberal Democrats' numbers are dreadful throughout the poll. Lord Ashcroft is one of the people least willing to write off Clegg's party. Only yesterday, in his much-reported memo to Lynton Crosby, he states that "people in Lib Dem-held constituencies are much more likely to say they will stay with the party". Nonetheless the poll pours cold water on any idea that the Lib Dems have won serious economic credibility from joining the coalition government. One result, in particular, stands out – 46% say the Tories have the best overall approach to dealing with the economy. The Labour number is 42%. The Lib Dems are way down on just 12%.

10. Boris Johnson is the politician that voters feel most positively towards. On a scale of zero to 10 (where zero equals most negative and 10 is most positive) David Cameron scored 4.69 compared to 4.55 for the Labour leader. Boris, at 5.99, was the only politician named who got more than halfway up the scale, with more voters feeling, on the whole, positively towards him than felt negatively. William Hague came second with a 4.94 average ranking.

• The poll was conducted nearly one month ago – between 17 and 28 October. Go to Lord Ashcroft polls for more detail