The voice uncannily resembles President Mugabe's. “I gave you maize for my election campaign and you made popcorn out of it,” it drones. “I gave you fertiliser and you made kachasu [bootleg] out of it. I gave you cattle and you sold them to the butcher. My people are a terrible disappointment.”

The listeners, crouched over a mobile telephone, convulse with laughter. The voice belongs to a mimic who satirises the speeches of the 84-year-old leader.

Then there is the new ringtone being sold at markets around the country. To the tune of a well-known “revolutionary” song of the ruling Zanu (PF) party of Robert Mugabe, the singers chant derisively: “And for how long are you going to vote for Zanu(PF)?”

The electronic trinkets are part of an onslaught of mockery of Mr Mugabe and his party as he tries to add five more years to the twenty-eight already in power. Only two months ago political satire such as this would have attracted the attention of the Central Intelligence Organisation. But in the absence of the customary intimidation by the brainwashed youth militia and war veterans, the police and the army that has preceded every election since 2000, the climate of terror that has kept Mr Mugabe in control has lifted.

I watched a group of children in the back of a pick-up truck playing hand games yesterday. Not pat-a-cake but the open palm salute of the opposition party Movement for Democratic Change (MDC) and the clenched hands of Simba Makoni, the former Finance Minister who has become a popular independent presidential candidate.

At a weekend rally Morgan Tsvangirai, the leader of the larger faction of the divided MDC, was welcomed by 30,000 open palms and red cards to “send off” Mr Mugabe.

The posters for Mr Tsvangirai list a series of fouls for which Mr Mugabe is being sent off, such as destroying the economy. The posters for Mr Makoni make no word plays but his beaming, boyish face shines out from them, in contrast to the menacing “vote for the fist” declared by Mr Mugabe's, which picture him in a Cultural Revolution propaganda pose, raising his fist in the Zanu (PF) salute and promising hungry, outraged Zimbabweans “revolution, yesterday, today, tomorrow”.

Mr Mugabe made a stiff joke at the weekend about the parties' salutes, asking: “Why do the MDC wave at the British when we should strike them with the fist?”

A poster war is being waged throughout the country. When I passed through the northern town of Chinhoyi last week the walls were plastered with mostly Tsvangirai and Makoni campaign posters. That night, before Mr Mugabe appeared there, they were papered over with “the fist”.

At the beginning of the campaign, coverage by the only permitted, and state-owned, television service in the country was giving Mr Mugabe 202 minutes' news coverage in a month against 9 minutes for Mr Tsvangirai. It has reduced to 86 per cent since 11 days ago, coincidentally at the same time that the observer mission of the Southern African Development Community, the 15-nation regional alliance, arrived.

Since then Zimbabweans have also had the experience of seeing, for the first time in 28 years, full-page advertisements placed by opponents of the regime in the daily press, which is controlled by the ruling party.

There is clearly anxiety now that the observers are not going to rubber-stamp Mr Mugabe's election.

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