Last week, Labour unveiled its latest weapon in the battle against the Conservatives: a cartoon chameleon called Dave.
Dave stars in an animated party political broadcast designed to highlight what Labour sees as David Cameron's inconsistent approach to policies - changing them to suit the voters he's courting.
Backed by the Culture Club song Karma Chameleon, the film follows the life of Dave, from egg to party leader.
Mark Lucas, a Labour spokes-man who worked on the campaign, says: "We are making a political point - David Cameron will tell audiences whatever he thinks they want to hear while remaining a true-blue Tory underneath. We think this needs exposing, but in an imaginative way."
Not everyone thought the film achieved this after it was shown on the BBC. The broadcaster received numerous complaints from viewers who felt the attack too personal and were disappointed there was no mention of Labour policies.
The personal nature of the film has raised questions about what political advertising is meant to achieve. It is rarely designed to change voters' allegiances. Winston Fletcher, a former advertising advisor for the Liberal Democrats, says: "The only research that has ever been carried out in this field said that effective advertising only persuades between 1.2 and 1.5 per cent of people to change political allegiance."
Chris Powell, a DDB London director who worked on the Labour account in 1997, believes the effectiveness of political ads can't be measured in the normal way because they are inherently different from commercial advertising.
"Commercial advertising is the only way for a brand to talk to its consumer, whereas politicians are constantly talking to the public. A party's advertising needs to be on the extreme side because it has to stand out," he says.
This is also the reason why political ads rarely mention policies. Powell adds: "Focus groups always ask why ads don't give more information about the policies. The answer is because if the ads were filled with policy, viewers would fall asleep. However, a good political ad should hit three criteria: have a relevant theme; be a flagship for party workers and supporters; and create further publicity."
In recent years, publicity has become the most important factor and if a political ad does not hit the front pages of the broadsheets, it is seen as a massive disappointment. One way to guarantee headlines is to attack the opposing party. The Tories' 1979 "Labour isn't working" and 1997 "demon eyes" ads are classic examples. The latter was banned by the Advertising Standards Authority for depicting Tony Blair as "sinister or dishonest".
However, Jeremy Bullmore, a member of WPP's advisory group and an advisor to the Liberal Democrats, sounds a note of caution: "Negative advertising can act with the brutality of a guillotine, but personal attacks can backfire wonderfully. Victorian values look a bit moth-eaten when half your cabinet are having a bit on the side."
The consensus is that Dave the chameleon has the potential to backfire on Labour . Fletcher says: "The ad reeks of panic. Many believe that Labour will rue the day it created Dave the chameleon. It makes Cameron look likeable. And, let's not forget, he has three years to sort out his policies."
- Got a view? E-mail us at firstname.lastname@example.org
LIB DEM EXPERT - Jeremy Bullmore, member, advisory group, WPP
"Very rarely can political advertising persuade someone to change their political allegiance. It can, however, make people hesitate. The unknown is scary; change is unnerving.
"The image of Dave is charming and I've warmed to Cameron a lot since seeing the chameleon on his bicycle. I now look at him with hesitant respect, so it probably hasn't worked this time. The film shows that Labour clearly see Cameron as a threat.
"People say they vote for policies but, in fact, they vote for a party's brand values, which are increasingly epitomised by the party leader."
LABOUR EXPERT - Mark Lucas, spokesman, Labour Party
"Political advertising can't change votes on its own. It must always work to support the political strategy. When the strategy is right and the creative execution strong, it can have a massive effect.
"Political advertising only works if it draws attention to a truth, and that's what we are trying to do. The public are not stupid and they rightly won't waste their attention on a nasty, baseless attack. That's why something like the 'demon eyes' campaign was such a mistake. It was nasty, confused and had nothing of substance to say. Our campaign is different - it has a clear point to make but in an interesting way."
CONSERVATIVE EXPERT - Lord Bell, chairman, Chime Communications
"That question is really impossible to answer, as it depends on the politics of the time and many campaigns have different agendas. However, a good campaign should capture the imagination, say something relevant to the party supporters and create extra communication.
"However, the latest Labour campaign is going to boomerang on them and have the opposite effect from the one they intended, because it attributes positive values to David Cameron.
"They have made exactly the same mistake that we did in 1997 with New Labour, which goes to show that lightning can strike twice."
LABOUR EXPERT - Chris Powell, director, DDB London
"Political advertising works on numerous levels, but isn't generally used to sway voters.
"Take Labour in 1997 - with a 20-point lead, we weren't trying to convince anyone to change. We were reminding them of the reasons they had changed in the first place.
"However, people do tend to object to personal slagging-off, but identify with a point of opposition policy they disagree with.
"The danger with making a personal attack is that it can blow up in your face."