Over 10,000 people have called for the closure of DESO (Defence Export Services Organisation), a Government unit which exists to find sales for private arms companies.
A petition received today by the Treasury contained signatures from people across the UK, including prominent names such as economist Samuel Brittan, writer George Monbiot and comedian Mark Thomas.
It follows a statement last year signed by thirty UK Church leaders, calling for the closure of DESO.
As the petition was handed in, arms traders and Government officials met in central London for DESO's annual symposium, which will be met with a peaceful demonstration organised by Campaign Against Arms Trade (CAAT) and the Fellowship of Reconciliation (FoR).
The demonstration and petition follow months of increasing criticism of DESO over its role in the sale of arms to despotic regimes, including BAE Systems' recent deals with Saudi Arabia.
A confidential DESO report, released under the Freedom of Information Act, revealed that Iraq and Libya were now 'priority' markets for DESO's arms push, as are Colombia and Kazakhstan - both criticised for human rights violations.
CAAT spokesperson Symon Hill said: "DESO plays a central role in the arms trade's cycle of destruction and poverty. It takes money from UK taxpayers and contributes nothing to the UK's defence. Thousands of people from all walks of life and political backgrounds have today insisted that DESO must be shut. The outcry is getting louder. Blair and Brown can no longer ignore public opposition to DESO."