UK arms deliveries were worth some £1.9bn in 2004, according to figures quoted by Amnesty from the International Institute for Strategic Studies.
The IISS lists the UK as fourth in a list of leading arms suppliers, after the US, Russia and France, but Amnesty said Britain's industry in many ways is "quite well-regulated compared to many other countries", adding it is among the 35 with legislation.
Amnesty International members will lobby MPs today for tough controls on the multi-billion pound international arms trade ahead of UN talks next month.
Some 200 people are expected to descend on parliament as a new report reveals a network of weapons transporters and brokers - including UK-based companies - fuelling the world's bloodiest conflicts.
The new report from Amnesty International and TransArms, entitled Dead on Time - Arms Transportation, Brokering and the Threat to Human Rights, reveals a worldwide trade, involving the delivery of hundreds of thousands of tonnes of weapons.
The organisation says an increasing proportion goes to developing countries, where they have fed some of the most brutal disputes.
And it claims the industry is barely regulated, with weak and outdated controls, and just 35 countries having laws to govern the activities of brokers and transporters.
Amnesty International's UK director, Kate Allen, said: "The arms trade is out of control and costing hundreds of thousands of lives every year.
"The UK has a real chance to do something about it when the UN meets in June and we want MPs to tell the government that their constituents really care about this issue.
"Arms brokers and transporters have helped deliver the weapons used to kill and rape civilians in Sudan and the Democratic Republic of Congo.
"Yet only 35 states have laws to regulate brokers. Countries need to get tough on the dealers and transporters of weapons.
"And we need an arms trade treaty to bring the whole industry under control, and stop weapons being sold to human rights abusers."
UK arms deliveries were worth some £1.9bn in 2004, according to figures quoted by Amnesty from the International Institute for Strategic Studies.
The IISS lists the UK as fourth in a list of leading arms suppliers, after the US, Russia and France, but Amnesty said Britain's industry in many ways is "quite well-regulated compared to many other countries", adding it is among the 35 with legislation.
The UK government has indicated it will champion an arms trade treaty at the UN next month, Amnesty says.
The report reveals hundreds of thousands of weapons and millions of rounds of ammunition were transported last year, supposedly to Iraq, from Bosnia and Herzegovina's wartime stockpiles.
Weapons were exported clandestinely under the auspices of the US Department of Defence using a chain of private brokers and transport contractors, including an air cargo company that had violated a UN arms embargo on Liberia. Amnesty says it remains unclear whether the cargo ever arrived in Iraq.
The reports cites examples of "unregulated, secretive and unaccountable" arms transporting and brokering, and makes a series of recommendations including the establishment of an international arms trade treaty to provide global standards for the arms trade, together with specific national laws.
Sergio Finardi of TransArms said: "It is clear that the existing patchwork of regulations are completely failing to keep pace with the expanding number and reach of international brokers, logistic firms and transporters.
"Such intermediaries may ensure that shipments of arms around the world arrive dead on time, but all too often they are used for the killing, rape, torture and displacement of hundreds of thousands of people."
