Members of Russian punk band Pussy Riot have jetted to London to attend a music festival curated by singer/artist Yoko Ono. Three members of the feminist collective were sentenced to prison stints last summer (12) after being found guilty of hooliganism following a performance of a protest song against President Vladimir Putin at a Moscow church. Yekaterina Samutsevich has since been freed, while fellow bandmembers Maria Alekhina and Nadezhda Tolokonnikova are still behind bars. John Lennon's widow Ono invited another pair of musicians from Pussy Riot to attend her Activism Weekend at this year's (13) Meltdown festival and admits she was impressed by their bravery as they spoke out on behalf of their jailed bandmates. She says, "It was so important. It shows that rebellion and revolution is (sic) worldwide actually. It's actually much harder for them (to speak out) in Russia. What they're doing to stand up is extremely daring and courageous. I just met the two of them here - incredible power, I thought the incredible power of innocence, in a way, is beautiful." Speaking to reporters about their imprisoned bandmates' plight, the duo wore balaclavas and asked for their voices to be disguised to retain their anonymity. One star told the BBC, "(They) are still in detention camps. According to the verdict, they are supposed to be there until March 2014, but we'll do our best to get them released earlier. Where they are now in detention camps there are about 100-120 people in one big room so the conditions are very bad and it's just a work camp, a forced labour camp."