A common complaint about politics is that it is treated more like a commercial battle between competing businesses than a principled struggle between competing ideologies. But proudly and with no apology, I look in this article at our parties through the prism of the most vital of all commercial qualities: the strength of their “brand.”

The analysis here concerns each party’s reputation. Past articles have—and future articles will—consider rival policy positions. This one explores the factors that are more likely to sway the floating voters who will decide next year’s general election: people with no fixed political home and who generally pay less attention to specific policies than general perceptions of the parties seeking their votes.

For more than a year, YouGov has been tracking party reputations by asking people whether they agree or disagree with each of 20 statements: six each about Labour and the Conservatives, and four each about Ukip and the Liberal Democrats. We tested equal numbers of positive and negative statements about each party. Here, for the first time, is what we have found—and the memo a political strategist might write to each party leader.

David Cameron

Just one of the six statements shows the public is on your side—but it’s a huge positive: by 52-36 per cent, voters agree that “the Conservatives have taken the tough but necessary decisions to get Britain’s economy growing again.” You are plainly right to make this claim the heart of your election campaign.

However, you have some big negatives that urgently need addressing: most voters reckon your party is out of touch, too obsessed with Europe, and not really committed either to better public services or helping all groups in society. These criticisms are shared by up to half of the people who voted Conservative in 2010. Many of them now support Ukip.

Indeed, as many as 60 per cent of current Ukip supporters think the Tories are “too obsessed with Europe instead of tackling problems here in Britain.” Don’t imagine you can win back the votes you have lost to Ukip by turning into a passionate Eurosceptic. Ukip leader Nigel Farage will always outflank you. Instead, you need to persuade the voters you have lost that you really are determined to improve the daily lot of ordinary voters, and know how to do so.

You have made little progress in the past 12 months. More people now agree that you have taken the right decisions on the economy, but your figures remain stubbornly high for being out of touch and not really caring about public services or wanting to help “all groups in society, not just the few.”

To secure an outright majority next May, you must tackle these problems urgently. You have talked the talk; now you must walk the walk. You need big symbols of your intentions, not just minor gestures. Show that you are more concerned to stop energy companies ripping off consumers than kicking families on housing benefit out of homes with a spare bedroom; prove that you are true allies of teachers, nurses and local government workers, not carping critics who want to keep down their pay and force through half-baked reforms.

You keep saying that we are all in this together. Most people don’t believe you, even though they agree that tough measures have been needed to reduce the deficit. The biggest danger you face now is that the voters of middle Britain will fear that, having borne the brunt of the hard times, they will see few of the fruits of recovery. If you can show that those fears are misplaced, you should win next year. If you can’t, you won’t.

Ed Miliband

If you were a religious man—which I know you are not—I would recommend getting down on your knees and praying that Ukip continues to cause problems for the Conservatives. There are few signs in YouGov’s findings that Labour has a strong enough “brand” to win next year without help from its opponents. You are in the same position that Arsène Wenger has faced towards the end of each season for as long as I can remember: knowing that Arsenal has too few points to ensure a top-four finish by its own exertions. The club’s rivals have to stumble, too.

That said, there are things you urgently need to do. Of the six Labour statements we tested, the two that produced the most alarming results are that “Labour still hasn’t faced up to the damage they did to Britain’s economy” (agree 60 per cent, disagree 26 per cent) and “Given the scale of the problems that Britain faces, Labour’s leadership is out of its depth” (57-28 per cent).

It’s probably too late to reverse those figures. The best you can hope for, and need to work for, is to narrow the huge gap between “agree” and “disagree.” In the past 12 months the numbers have simply not shifted. You probably hoped that memories of the Gordon Brown years might fade with time, and criticisms might be muted as the coalition fails to lift living standards. So far, those hopes have been dashed.

Even if Labour’s reputation for economic competence is not as dire next May as it is today, it won’t be the vote-winner that it was in the era when Tony Blair was Prime Minister and Gordon Brown Chancellor. So you need to win votes by exploiting Tory weaknesses. Persuade people you can improve public services and will do so without raising taxes. To win the next election, you need more people to credit you with the ability and determination to do these things. Again, you have made no progress in the past year.

Paradoxically, Europe could be another vote-winner. Fewer voters are opposed to British membership of the European Union as many right-wing MPs, activists and commentators think. You have the chance to offer yourself as the leader who can protect jobs and prosperity by removing the uncertainty that could afflict Britain in the two years between a Conservative victory and a 2017 referendum. But only 31 per cent think you would “stand up for Britain’s interests in Europe.” Push that figure to 40 per cent and you will harvest extra votes.

Nick Clegg

Oh dear. I can bring you little comfort. It’s not just that too few voters think well of the Liberal Democrats on any of our four measures. It’s that your critics include a great number of people who voted Lib Dem in 2010—and that if anything, your party’s brand image is getting worse, not better.

Overall, the proportion of voters who say they don’t know what you stand for has remained a steady 73 per cent or so for more than a year; and those who say you have sold out your principles by going into coalition amount to an equally steady 55 per cent.

As for the positive statements, the numbers agreeing have declined: the already low 25 per cent who thought the Lib Dems were a sensible party of government six months ago has dipped even further, to just 21 per cent, while the 34 per cent who agree that “the Liberal Democrats have stopped the Conservatives doing various things that would have been bad for ordinary people” are among the lowest in our series.

Now, given that even in 2010 only 24 per cent voted Lib Dem, the hostility of people who have never supported you is neither surprising nor worrying. But consider the views of those who did vote Lib Dem four years ago. Two-thirds of them don’t know what your party stands for and 56 per cent say you have sold out on your principles. Only one in three think you have shown that you lead “a sensible party of government.” On only one measure do even half of your 2010 voters give the party some credit: 52 per cent think you have put a brake on some of the Tories’ measures “that would have been bad for ordinary people.”

That last figure offers a clue about what you should do now. A good rule of marketing is to build on what your target customers already think, rather than persuade them that they are wrong. Among the voters who have deserted you since you went into coalition are more than one million who accept that you have had a moderating influence on the government. As the election approaches, and you command more media attention, that is probably the message most likely to persuade the voters you need to win back.

Nigel Farage

You are understandably delighted with your coup in securing Douglas Carswell MP’s defection from the Conservatives. He is almost certain to win the coming by-election in his constituency of Clacton, probably by a big margin; and I would expect him to hold the seat in next May’s general election. You must now have a good chance yourself of winning Thanet South; and Ukip might chalk up one or two more victories (Grimsby? Yarmouth? Thurrock?).

However, while Carswell’s defection generated a torrent of publicity, it has only marginally improved Ukip’s “brand” ratings, which are not that great. Here are the main figures from our survey conducted immediately after Carswell announced his defection on 28th August, compared with our figures from early August:

Net agreement (that is, the percentage agreeing minus the percentage disagreeing):

• “Ukip is full of oddballs and extremists.” Before Carswell, plus 25; after Carswell, plus 24

• “A vote for Ukip at the next general election would be a wasted vote.” Before, plus 18; after, plus 13

• “Ukip is more in tune with the concerns of people like me than the other three parties.” Before, minus 13; after, minus 17

• “Leading Ukip politicians are more trustworthy than those of the other three parties.” Before, minus 48; after, minus 47.

Your immediate task is to start to turn those figures round. The Clacton by-election, on 9th October is your chance. The test you need to set yourself is not just to win it handsomely, but to persuade voters around Britain to rethink their view of your party. Otherwise, the danger you face is that your support will be squeezed in next year’s general election campaign, as voters decide that they want to cast their vote to get the government they want—or to keep out the party they dislike most—rather than to “send a message” (about Europe, immigration, crime, Britain going to the dogs, or whatever) which is what they have been doing in local, European and by-elections, and may well do in impressive numbers in Clacton.

Finally, prepare yourself for the possibility—maybe likelihood—that you will win more votes in May than the Liberal Democrats but far fewer seats. The Lib Dems used to complain bitterly about the way our voting system treated them. They started to break through only when they stopped banging on about the unfairness of the system, and devoted their efforts to building up support locally. You have a good chance to succeed in time in the same way. Concentrate on that and leave the fairness argument to others. Voters don’t like the sound of parties grinding their own axes on such matters.

There is one further lesson from “brand” politics that you should all heed. Successful companies attack their rivals sparingly, and then only on narrow grounds of demonstrable fact—that one supermarket sells Nescafé more cheaply than its rivals, say, or one airline provides more legroom than another. There is a reason for this: generalised abuse is counterproductive.

Sadly, negative election campaigning does sometimes work—the Conservatives attacking Labour on tax in 1992, or Labour targeting William Hague and Michael Howard as right-wing extremists in 2001 and 2005. But in the end, relentlessly negative campaigning from all sides simply exacerbates public cynicism towards all the main parties. Just imagine what would happen if each car maker devoted most of its marketing budget to accusations that it produced unsafe vehicles. Would we be surprised if fewer people ended up buying cars at all?

So here’s my suggestion. Get together and agree that each of you will talk only about your own policies, your own leading figures, your own ability to run Britain and your own vision for its long-term future. Respect each other’s intelligence, honesty and good faith. You behave in a perfectly civil manner to each other in private, and in all-party gatherings and select committees. Try extending the practice to television studios and Prime Minister’s Questions.

You won’t do it, of course. But you should.