Activists and human rights campaigners expressed dismay this weekend after the Portuguese parliament failed to condemn the long sentences given to the so-called Luanda Book Club – the 17 dissidents convicted of political defiance of Angola’s government.

The former colonial power had been warned by the Angolan president, José Eduardo dos Santos, against “interfering”, but the blocking of a motion in Lisbon to repudiate the verdicts was attacked by campaigners for the jailed men as “complicity in the ongoing looting” of the country by the regime.

The group – including rapper Luaty Beirão, writer Domingos da Cruz and political T-shirt seller Nito Alves – were arrested for holding a meeting at which they discussed books, including one by Gene Sharp about non-violent protest, which was entitled From Dictatorship to Democracy.

After a lengthy remand period, which included several of the activists going on hunger strike, and a trial on charges ranging from conspiracy to plotting, all 17 were sentenced last Monday to terms ranging from two to eight-and-a-half years, with hefty fines. Beirão was given five-and-a-half years for “falsifying documents” and journalist da Cruz was given the longest sentence – “for leading the criminal association”.

One activist, Francisco Mapanda, was later sentenced to eight months for contempt of court after shouting in the courtroom, “This judgment is a joke.”

Both the prosecution and defence lawyers said they would mount appeals. There is particular concern about the state of health of teenager Alves and of Professor Nuno Dala, who has been on hunger strike for 19 days.

The Albert Einstein Institution has strongly condemned the men’s trial, as has the Human Rights Foundation in New York, which called on the Angolan government “to vacate the convictions and release the activists immediately”.

All 17 have been adopted as “prisoners of conscience” by Amnesty International, which has called for their immediate release and dismissed the trial as a “mockery of justice”. Its director for Southern Africa, Deprose Muchena, said: “The activists have been wrongly convicted in a deeply politicised trial. They are the victims of a government determined to intimidate anyone who dares to question its repressive policies.

“This unjustifiable conviction and draconian sentences against these peaceful activists, who should never have been detained at all, demonstrate how Angolan authorities use the criminal justice system to silence dissenting views. They should not have spent a single day in prison.”

Lisbon was the scene of angry demonstrations last week in support of the activists and to protest at the influence of Angolan tycoons who have been investing in Portugal’s cash-strapped news and telecommunications industries, something that has been called “reverse colonisation”.

Further protests were planned for this week to coincide with similar demonstrations in Luanda, where the convictions have caused deep anger especially among young Angolans who are increasingly using rap music to protest, said political writer Rafael Marques de Morais who called it “Angola’s most defiant genre”.

“Despite the state’s efforts to withdraw sponsorships and subsidies from pro-people hip-hop artists, they continue to use the internet, flash disks, blank CDs, taxi operators and street vendors to distribute their message,” he said.

“The Angolan authorities always proclaimed to have caught this group ‘red-handed’ in their crime. That crime was reading a book,” said Vicky Baker, deputy editor of Index , the Index on Censorship’s magazine. “Evidence was so scant of the alleged coup-plotting that those charges had to be dropped. It is absurd and tragic that these young men have been convicted of rebellion and must now see out jail terms.

“This has been another sham trial, similar to the one we saw last year with Rafael [Marques de Morais], who was convicted of defamation after writing a brave and much-needed exposé of the country’s blood diamond industry.”

Monday marks the 14th anniversary of the end of Angola’s 26-year civil war which began after independence from Portugal. Dos Santos, 73, has been president since 1979 and has been accused of presiding over one of the world’s most corrupt regimes, amassing a fortune for himself, his family and friends while two thirds of his country lives below the poverty line. Dos Santos is worth an estimated $20bn.