"IF you can't say anything nice, don't bother saying anything at all," my mother used to bawl whenever, as kids, me and my brothers indulged in name-calling.

So heaven knows what she would have have made of Michael Howard's election strategy. Pulling no punches, cushioning no blows, the Tory leader has branded the Prime Minister a "liar" over Iraq.

In the most direct attack on Tony Blair's character and integrity, the Tories' latest election poster reads: "If he's prepared to lie to take us to war, he's prepared to lie to win an election."

The significance of this should not be underestimated. Among politicians, the four-letter 'L' word is taboo. Any MP using it in the House of Commons faces censure - and possible suspension.

But with polls indicating Labour is heading for a historic third term in power on May 5, Mr Howard has resorted to targeting what he believe is Mr Blair's weak spot: the trust factor.

Whether Iraq and what legal advice the PM did or did not receive from the Attorney General before committing British troops in March 2003 really concerns voters is debatable.

Yes, there is considerable anger among Labour-ish middle-class voters about the war and the way Mr Blair sold it to the people. That Iraq is better without post-Saddam is unlikely to abate their fury. But most of Britain has known where they stand on the war since it became clear two years ago that the weapons of mass destruction had mysteriously disappeared.

Why this has suddenly become an issue, alongside the increasingly negative nature of the Tory's campaign, can be ascribed to one man: Lynton Crosby, the party's elections supremo.

His reputation is built on masterminding four successive general election victories for Australian Prime Minister John Howard's Liberal (ie Conservative) Party - using highly-controversial tactics.

In Australia, he authorised some of the most ruthless political campaigns. In one advert he linked the ruling Labour Party's "soft" sentencing policy to the murder of a young woman by an Aboriginal man.

In 2001, he claimed Australia was being "invaded" by asylum seekers with links to terrorism. They threw their children overboard to force the authorities to allow them to land, said Crosby. Completely untrue. But John Howard swept to victory.

Such "dog whistle" issues, including immigration and crime, coupled with personal attacks and innuendoes against Labour candidates are particularly effective in Britain's marginal constituencies.

Mr Blair has dismissed the Tory attacks as proof they have a paucity of workable policies: "Let the Tories go negative, negative, negative. I will stay focused on education, education, education."

But he must shoulder some blame. Embroiled in controversy following the 1997 election - remember the Government exempting motor racing from a tobacco advertising ban after Formula One boss Bernie Ecclestone donated £1 million - he urged voters to trust him, claiming: "I'm a pretty straight sort of guy".

He chose to put his character into the political arena, so he can't complain if others take him at his word. Mr Blair has hardly been whiter-than-white when it comes to mixing personal attacks with the political. What about those "pigs might fly" posters at the start of the pre-campaign? And he's not been shy at claiming shadow chancellor Oliver Letwin would be "scary" controlling the nation's purse strings.

These jibes are considered part of the rough-and-tumble of politics. For instance, when voters in marginal seats are reminded of Michael Howard's record in Government: the hated poll tax, economic recession, negative equity, repossessed houses, spiralling interest rates, unemployment.

As my mother might say: "People in glass houses really shouldn't throw stones."

Updated: 11:06 Friday, April 29, 2005