TBWA\London unveiled a poster showing a picture of Michael Howard with his four predecessors in the Tory leadership (Margaret Thatcher, John Major, William Hague and Iain Duncan Smith) and the copy: "Britain is working. Don't let the Tories wreck it again."
The slogan was a deliberate echo of the "Labour isn't working" theme which shot Saatchi & Saatchi to prominence at the general election in 1979.
But the Tories accused Labour of "stealing" the ads they produced at the 1987 and 1997 campaigns, when they opted for ads that claimed "Britain is great again. Don't let Labour wreck it" and "Britain is booming. Don't let Labour blow it" respectively.
A Tory official said: "It seems that Labour's campaign team has run out of ideas, just like the Government as a whole. The best they can do is to steal ours."
In fact, the Tories first used the idea at the 1959 election, when Colman Prentis & Varley produced an ad saying: "Life's better with the Conservatives. Don't let Labour ruin it."
A Labour source dismissed the criticism from the Tory Party, saying: "There are only a certain number of simple messages you can use when you are in power and one of them is to warn voters not to let the other side back in and make a mess of it. The Tories don't like it because it reminds them that they are out of office."