A senior Zambian police commander defended on Monday the right to protest of six activists on trial for staging a demonstration at parliament over a $42m firefighting procurement deal. Hip-hop star Chama Fumba, known as Pilato, led last year's picket over fire engines costing $1m each, seen as emblematic of corruption fostered by President Edgar Lungu."The accused have a constitutional right to demonstrate and they complied with the Public Order Act," said Lusaka province deputy police commissioner Geoffrey Kunda in evidence to Lusaka magistrates' court.Kunda said his office failed to respond to a notice given by the protesters signalling their intention to picket parliament during the finance minister's budget speech on September 29, 2017."I think it could have been an omission on our part. That was an omission and not deliberate," Kunda said.He added that an attempt to verbally ban the march may have led to the situation and the arrests of the campaigners.The six have pleaded not guilty to charges of disobeying a lawful order and insisted they had a right to protest within the grounds of parliament.Magistrate Mwaka Mikalile ordered that the trial should continue on November 29 and 30."Since 2017 we have had scandal after scandal... Can our money stop being stolen?" asked accused activist Laura Miti, speaking outside court."As long as we are here and the thieves are not here we will continue to protest."Fumba was arrested in May when he returned to Zambia from South Africa, where he had fled after his hit song, "Koswe Mumpoto" (Rat in the Pot), drew angry reactions from supporters of Zambia's ruling Patriotic Front (PF) party.The track was widely interpreted as a protest song accusing President Edgar Lungu and his government of being corrupt.Zambia's opposition has accused Lungu of increasingly authoritarian behaviour.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.