Hundreds of campaigners, including many Christians, have formed a human chain around the headquarters of DESO (Defence Export Services Organisation), a Government unit that secures business for private arms companies.
They encircled DESO's central London offices on Monday calling for DESO to be shut and labelling the building a "Global Danger Zone".
The chain involved about three hundred people, including comedian Mark Thomas and Christian peacemaker Norman Kember, who survived kidnapping in Iraq.
The peaceful demonstration highlighted the role of DESO in using taxpayers' money to benefit arms traders and in marketing weapons to brutal regimes such as Saudi Arabia.
Participants travelled from all over Britain to join the chain, which attracted significant support from people living and working locally. The event was followed by a lobby of Parliament.
Mark Thomas, writer and comedian said: "When taxpayers' money is used to subsidise arms deals, we are complicit in those deals. We are here to say 'No! We will not be complicit!'"
Anna Jones of Campaign Against Arms Trade (CAAT) added: "People from all walks of life have today said that DESO must be shut. The British public do not want their taxes funding a marketing agency for private arms dealers. We have sent a message that time is up for the Government's gunrunners."
The human chain included people of all faiths and none. Earlier in the day a prayer meeting was held outside DESO's headquarters by Christians calling for DESO's closure, including the Fellowship of Reconciliation and the CAAT Christian Network.
The campaign to shut DESO is backed by the Liberal Democrats, Plaid Cymru and the Green Party along with leading Labour backbenchers including Clare Short and John McDonnell.
It has the support of prominent religious leaders including Graham Carter (President of the Methodist Church), Colin Bennetts (Anglican Bishop of Coventry) and Patrick O'Donoghue (RC Bishop of Lancaster).
Thirty UK Church leaders recently signed a statement  calling for the closure of the government arms sales unit.
A confidential DESO report, released several week ago under the Freedom of Information Act, revealed that Iraq and Libya are now 'priority' markets for DESOís arms push, as are Colombia and Kazakhstan, both criticised for human rights violations.