Joe Churcher and David Hughes

Zimbabweans voted in a one-candidate presidential election yesterday as Foreign Secretary David Miliband joined international condemnation of the "sham" poll.

Widespread violent intimidation was reported across the country with voters being forced to back Robert Mugabe in the run-off following March's disputed presidential election.

Despite withdrawing at the weekend in protest at a brutal campaign against his supporters, opposition leader Morgan Tsvangirai's name remained on the ballot paper.

Foreign ministers from the world's richest countries, including Mr Miliband, accused Mugabe's regime of "systematic violence, obstruction and intimidation".

Movement for Democratic Change leader Mr Tsvangirai said the ballot had become "an exercise in mass intimidation, with people all over the country forced to vote".

He advised his supporters to vote for Mr Mugabe rather than risk further violence at the hands of the president's Zanu-PF supporters. "It makes no difference because the vote is a fraud anyway," said Mr Tsvangirai. Yet many Zimbabweans decided to "throw caution to the wind" yesterday by going to the polls to "vote for change".

Lovemore, who lives in one of the high-population density areas outside the capital, Harare, with his wife and newborn child, said he voted for the opposition MDC. The 35-year-old, who would only give his first name, said all the residents of his area were visited this morning by pro-government groups urging them to vote for "peace".

They were told that under "Operation Indelible Ink", the government would know who they voted for. Lovemore said he was told that if he did not want war, and if he wanted his wife and son to be safe, he would have to vote for Zanu-PF.

"They told us early in the morning that everyone should go and vote and if you don't go, it means you are listening to the message to boycott the election," he said. "I'm sure quite a number of people were intimidated into voting."

He said the group told people to write down the serial number on their voting slip so that they could later check who they had voted for. At the polling station, he described a "deliberate attempt from officials to try to intimidate the people coming to vote".

He said there were no election observers at the polling stations and Zanu-PF officials examined identity cards and asked to be shown voting cards after they had been marked. Lovemore said that up until now, he had complied with government "thugs" for the safety of his family.

This included carrying a party card, wearing the party T-shirt and chanting the slogans when confronted. But in the polling booth, he was determined not to comply, even though he said he could not see how President Robert Mugabe's party could lose.

"We are all so angry here with everything," he said. "We are trying to throw caution to the wind, to think that maybe something positive can come from our votes. We are just trying to play our role." Meanwhile, the political heat on Mr Mugabe from around the world was building.

In a statement issued at the close of a two-day meeting in Kyoto, Japan, G8 foreign ministers said: "We deplore the actions of the Zimbabwean authorities - systematic violence, obstruction and intimidation - which have made a free and fair presidential run-off election impossible.

"We will not accept the legitimacy of any government that does not reflect the will of the Zimbabwean people."

Campaigners in the UK marked the election by carrying a ballot box in the shape of a coffin, symbolising the death of democracy in Zimbabwe, through central London.

Earlier this week, Africa's most revered political figure, ex-South African president Nelson Mandela, finally broke his long silence on the issue to denounce Mr Mugabe's failure of leadership.

Britain has been leading calls for tighter sanctions against what Prime Minister Gordon Brown has described as the "criminal cabal" which makes up Mr Mugabe's regime. In an indication of Washington's attitude to the Mugabe regime, Secretary of State Condoleezza Rice called the run-off a "sham" that "could not possibly produce a legitimate outcome".

The US would raise possible sanctions with other members of the UN Security Council, she added.

Archbishop Desmond Tutu called on South African President Thabo Mbeki to "turn the screws" on Mr Mugabe. Many Africans have questioned Mr Mbeki's unwillingness to openly criticise his neighbour.

The Archbishop said: "All African leaders, including our own president, should declare Mr Mugabe illegitimate if he claims he is the newly elected president of Zimbabwe."