The news from Zimbabwe grows more sickening by the day. The campaign of terror by President Mugabe's thugs to intimidate his opponents has led to the beating, torture and murder of whole families (see opposite page).

Yesterday four more MDC youth activists were found dead near Harare, abducted on Tuesday, killed and then dumped. Neither office nor popularity afford protection: the wife of the mayor-elect of Harare was seized and found dead later in a hospital. Others have been mutilated, set on fire with petrol or burnt alive in their homes. Reports from across the country tell of police, soldiers and militia gangs of so-called “veterans” being mobilised to silence MDC supporters, force villagers to attend pro-Mugabe rallies and imprison opposition activists in makeshift torture centres set up in country clubs.

The level of violence is fast approaching that of lawless warlordism, the kind of random terror used by rebels in Sierra Leone or sadistic death squads in Rwanda. Zimbabwe has done its best to hide these crimes from the world, banning journalists and election observers or, with cynical hypocrisy, blaming opposition activists for causing bloodshed and attempting to destabilise the country. Even to the country's neighbours, most of whom have deliberately turned a blind eye to the horrors of Mr Mugabe's paranoia, his brutalities are ever more evident. Several admit now that a fair election is impossible. Botswana sent a protest to Harare last week, and regional observers can see for themselves the “cleansing” of opponents now under way.

President Mbeki of South Africa, whose official role as a mediator is made meaningless by his partisan support of Mr Mugabe, flew north on Wednesday to urge both sides to cancel the election and form a government of national unity. His proposal was as feeble as his efforts to end the violence: not only would this entrench a tyrant and his cronies in illegal office, but it would also give a free hand to the shadowy military figures surrounding him who are determined to silence all those ready to speak out about the campaign of organised terror.

It is time the world let Mr Mugabe know that it is collecting evidence of what is happening for use in war crimes trials. The junta ordering the atrocities should know that at some time in the very near future it will be held to account. The world was unwilling to intervene while the killings were going on in Rwanda, Liberia or Sierra Leone, but it surely will not be so tardy in its response again. Mr Mugabe's henchmen are as guilty of crimes against humanity as those who carried out the ethnic cleansing in Bosnia and Kosovo and are still doing so in Darfur. The Army and police in Zimbabwe, many of whom are revolted by the orders they are given, are reluctant to disobey. But if they know that international retribution awaits those responsible for torture and murder, they may be emboldened to refuse this attempt to terrorise their countrymen.

News of the mounting atrocities is leaking out to the wider world, despite the restrictions on reporting. The evidence of ethnic cleansing and murder is compelling: starvation is now being used as a weapon, with food withheld from swaths of the country seen as disloyal or likely to vote for the opposition. This alone should be enough to prompt the United Nations to ask whether Mr Mugabe is not now committing crimes against humanity as plainly as other dictators against whom the world has taken action eventually. No country has fallen as swiftly or as far from tolerable prosperity to brutal inhumanity. If Zimbabwe's neighbours are too pusillanimous to act, the world must consider doing so before this disgraceful election causes the killing and torture of more innocent people.