Greenpeace has insisted it will not be "daunted" by the piracy charges facing environmental campaigners in Russia as supporters held a candlelight vigil to mark their 30th day in prison.
Six Britons were among 30 people detained last month when armed Russian officials boarded their vessel, the Arctic Sunrise.
The boat and Greenpeace protesters were taken from the Arctic's Pechora sea, near to oil company Gazprom's platform, to the port of Murmansk.
The six Britons, including videographer Kieron Bryan, who was documenting the protest, are being investigated for piracy, which carries a jail term of 10 to 15 years.
About 30 supporters gathered tonight outside the Russian embassy in central London holding candles and placards with photographs of each detainee to call for their immediate release.
Speaking at the vigil near Kensington Palace Gardens, Greenpeace Arctic campaigner Sara Ayech said the organisation would not be deterred from staging future protests in the Arctic.
"Greenpeace won't be daunted for standing up for the environment and for highlighting the impact of oil drilling on pristine and beautiful places like the Arctic," she said.
"This will not deter us.
"We think this is a ludicrous charge. They were protesting peacefully.
"We're very worried about them. This week there have been bail hearings but they've all been refused bail. We're really hoping for a swift resolution to this and we're hoping they're released very soon."
Eleven Nobel Peace Prize laureates have written a letter to Russian president Vladimir Putin calling for the piracy charges to be dropped, including South African archbishop Desmond Tutu and Northern Irish peace activists Mairead Maguire and Betty Williams.
The letter comes after Angela Merkel, the German chancellor became the first head of state to raise the issue of the crew's detention with Mr Putin, urging a speedy resolution of the case in a phone call.
The families of the six Britons involved have met with the Foreign and Commonwealth Office to discuss what was being done to bring their loved ones home.
Ms Ayech said Greenpeace was happy so far with the actions of the British government in attempting to secure the detainees release.
"We know Angela Merkel phoned President Putin to ask for a swift resolution to this case," she said.
"We know that David Cameron has offered assistance and has been asking for updates every day, particularly one of the detainees who is his constituent. We know the British government have been offering a lot of consular assistance.
"At the moment we're happy with what the UK government are doing."
Along with Kieron Bryan, activists Philip Ball and Alexandra Harris and second engineer Iain Rogers have been detained for two months pending a piracy investigation.
Two other British activists, Frank Hewetson and Anthony Perrett are also being detained, having had earlier bail applications denied.
Those arrested include citizens of Australia, Brazil, Canada, Denmark, The Netherlands, Finland, France, Sweden, Poland, Turkey and Ukraine and the US.
Greenpeace had been campaigning against attempts by companies to drill for oil in Arctic waters.
It warned a spill would be highly damaging to the environment and the extraction of more fossil fuels would add to climate change impacts.
Gazprom's plans to start drilling from the Prirazlomnaya platform in the first quarter of 2014 raised the risk of an oil spill in an area that contains three nature reserves protected by Russian law, campaigners have said.