“This is a travesty of justice,” Anwar declared after the conviction was delivered amid uproar in Kuala Lumpur’s Court of Appeal. "This has been choreographed."

The verdict has inflamed tensions in the country after divisive and disputed elections last year and shattered Anwar’s plans to take control of the country’s richest state.

International human rights groups have condemned the four-year pursuit of 66-year-old Anwar on a rarely used colonial-era charge as politically motivated and a miscarriage of justice aimed at ending his political career.

The conviction, which Anwar has appealed, blocks him from contesting a by-election on March 23 for Selangor, the country's most populous state, where he planned to become chief minister, providing a platform for him to launch a new bid to topple the government.

“It is a clear signal to the people of Malaysia that they [the government] are not interested in economic malaise but they are interested in killing their political opponents,” Anwar said.

Earlier Anwar, a former finance minister and deputy prime minister, said there was “absolutely no case” for him to answer and “this is clearly seen to be political”.

“You have got want you wanted,” Anwar shouted to the judges after the unanimous verdict was announced.

Judges allowed bail of $2973 to be posted on Monday.

Anwar’s 61-year-old wife Wan Azizah Wan Ismail, a leading opposition politician, wept in the packed court room and supporters chanted “reformation” and “free Anwar".

Anwar has been a potent threat to the Barisan Nasional coalition that has ruled the country since its independence from Britain in 1957.

His opposition has made deep inroads into its parliamentary majority in the past two national elections, winning the most votes at elections last May but falling short of an historic victory because of a gerrymandered electoral system that favours Muslim voters in rural areas.

Anwar was arrested in 2008 on charges of having intercourse with a male aide.

He had already spent six years in jail on sodomy and corruption charges after he was sacked as deputy prime minister in 1998 and lost his status as heir apparent to then prime minister Mahathir Mohamad.

He was found guilty of the 2008 charge but, after a long series of delays, the High Court in January 2012 acquitted him after a judge found that crucial DNA evidence submitted by the prosecution might have been compromised.

Human rights groups condemned the decision by prosecutors to launch an appeal against the acquittal.

The crime that criminalises “carnal intercourse against the course of nature” provides punishment of up to 20 years.

But the United Nations Human Rights Committee has ruled it contravenes international legal standards and should be abolished.

The International Commission of Jurists condemned Anwar’s conviction as a miscarriage of justice, saying it “casts doubts on the independence and impartiality of the Malaysian judiciary and tarnishes the reputation of the country’s legal system”.

The ICJ’s observer at the court was its commissioner Justice Elizabeth Evatt, a former chief judge of Australia’s Family Court.

A government spokesperson saidMalaysia had an independent judiciary.

“This is a case between two individuals and is a matter for the courts, not the government,” the spokesperson said.

Malaysia’s Lawyers for Liberty said the conviction on a “clearly trumped up and politically motivated charge” reaffirmed “the return of iron-fist authoritarian rule and Najib Razak’s false reformist credentials”.

Anwar’s wheelchair-bound lawyer Karpal Singh, 73, who is also a leading opposition figure, was found guilty of sedition last month, a law the government had pledged to abolish in the run-up to the last election. He faces sentencing on March 11.

Phil Robertson, deputy director, Asia division of Human Rights Watch, said Anwar’s trial “was all about knocking him out of politics and the government was prepared to do whatever it took to make that happen”.