By Tom Geoghegan BBC News Online

You have to be pretty committed to go to Belmarsh prison in a remote part of south-east London on a windy Sunday afternoon.

So it was no surprise to find a defiant mood among 150 protesters calling for the release of 13 men inside, held as terror suspects without trial.

Some protesters feared reprisals if identified

They took over a grassy knoll sandwiched between the prison grounds and the busy Western Way, armed with placards, whistles, drums and even police helmets.

A group called the People's Freedom Front, highlighting the plight of political prisoners in Turkey, led the chants.

Their presence symbolised the diversity of the crowd and the international nature of the issue.

Spokeswoman Sibel Hasan said: "The people in Belmarsh are in the same situation as our Turkish friends. We are here to be their voice."

The hope was that the men inside could hear the noisy support outside.

But a more permanent endorsement was being created in the shape of a book of messages, to be taken in to the prison by one of the lawyers.

"Do not give up hope," was one message which echoed the general mood.

'Not just Muslims'

Some of those attending claimed to have first-hand experience of persecution as a Muslim.

Asad Raja, known as MC Incyte, rapped a poem about always being picked out by customs officials when coming back from mainland Europe.

The 26-year-old from west London said he formed Double Negative, which performs protest rap on issues such as Palestine, because the music scene was too obsessed with guns and women.

Ms Ohe said it was important to show support

He said: "It's not just about Muslims, we all have to stand together as one."

Other young Muslims wore headscarves to hide their faces.

One of them said: "They see you're a Muslim protesting and think you're part of the terrorist organisation."

They were joined by people from many backgrounds, representing groups such as the Green Party, Stop the War and Campaign Against Criminalising Communities.

Others came unaffiliated to an organisation but eager to support the cause.

They are intending to brick them in forever Gareth Peirce Human rights lawyer

Weon Ohe, 31, a South Korean student in London, said: "I'm just interested in human rights. These men should be put on trial."

Sue Luxton, who is the Green Party candidate for Greenwich and Lewisham at the Greater London Assembly, said: "Lots of people living near here are completely unaware that people are being interned in this borough."

Not including a young boy riding past on his BMX, who stopped to listen as human rights lawyer Gareth Peirce thanked the crowd for showing the prisoners were not forgotten.

She told BBC News Online she intended to describe the rally to some of the detainees on Monday, who were "mentally distressed" by their continuing detention.