Roy Bennett, a leading opponent of Robert Mugabe, hailed a "return to the rule of law" in Zimbabwe after he was acquitted of plotting to overthrow the government.

The Movement for Democratic Change (MDC) said yesterday that it would push for the former coffee farmer to be sworn in as Deputy Agriculture Minister after a judge dismissed the case alleging his involvement in a terrorist plot.

The 53-year-old, who could have faced the death penalty if convicted, has insisted since his arrest in February last year that the charges were a ploy to undermine the MDC and prevent him taking his place in the government. His acquittal will boost the beleaguered Prime Minister, Morgan Tsvangirai, who has often appeared powerless to prevent the persecution of his allies and supporters.

"The state has failed to prove its case," Judge Muchineripi Bhunu told a packed courtroom in the capital, Harare, yesterday. "The accused is accordingly found not guilty."

Mr Bennett, who was already free on bail, told reporters: "This judgment gives hope that we are returning to justice and the rule of law."

The outspoken farmer from the Chimanimani mountains near the border with Mozambique has been among the most persistent and hated opponents of the Mugabe regime.

During the controversial land seizures that began in 2000, he was portrayed by the government as a colonial profiteer and stripped of his land along with hundreds of other white farmers. But Mr Bennett remains popular in his home district and was elected to parliament for the MDC, which was then in opposition.

The ruling Zanu-PF party's hatred of him can be traced to a scuffle with the Justice Minister, Patrick Chinamasa, who was stopped in the middle of a tirade against Mr Bennett's forefathers, whom he called "thieves and murderers", when the heavy-set farmer grappled him to the floor. Mr Bennett was punished with a 15-month prison sentence.

After his release he fled to South Africa where he became the treasurer general of the MDC. He helped run its election campaign in 2008 in which the party is widely accepted to have defeated Mr Mugabe, despite heavy intimidation and rigging.

When a power-sharing government was announced to end the post-election crisis Mr Bennett was nominated by the MDC for a ministerial post. Mr Mugabe later insisted he would not allow him to take up the post.

The state's case against Mr Bennett hinged on the evidence of Peter Hitschmann, a former policeman and arms dealer. Prosecutors produced emails that claimed to prove the former farmer's involvement in a 2006 plot to buy weapons. During the case Mr Hitschmann disowned the emails and said that previous statements implicating Mr Bennett had been extracted under torture.