The campaigners, which included more than 70 Traidcraft supporters, were protesting against new free trade deals known as EPAs, that the European Union (EU) is negotiating with African, Caribbean and Pacific countries. The deals, planned to come into force at the end of the year, threaten the livelihoods of millions of the poorest people in the world.
Similar events took place in more than 30 countries worldwide, including Fiji, Belgium and South Africa, as civil society, farmers and workers rallied against the proposed deals.
Glen Tarman, co-ordinator of the Trade justice Movement that organised the London rally, said "Today's event shows how widespread the concern is about the EU's unfair trade proposals. In the UK and around the world, people have come together to demand trade justice and a fair chance for poor people to get out of poverty.
"The UK and all other governments in the EU must listen to their concerns and realise that it is not acceptable to push free trade deals onto poor countries. These countries need the time and space to determine what policies are best for them to support sustainable development and reduce poverty."
Delivering the trade justice message
Campaigners of all ages gathered near the German embassy in Belgrave Square to listen to speeches delivered from an open-top bus by trade unionists, activists and NGO leaders from the UK and Africa.
The crowd gave a huge cheer as a small delegation made its way into the embassy to deliver hundreds of keys from the participants with the message 'Europe: don't lock Africa in to poverty'.
Germany was the main target as it currently holds the EU presidency and can use its influence to ensure that new trade deals promote - rather than undermine - development. German chancellor Angela Merkel has pledged to make development a cornerstone of the presidency.
The campaigners then moved off in groups to visit the other European embassies, the UK Department for Trade and Industry and the London office of the European Commission.
After meetings across the capital where embassy representatives accepted symbolic trade justice keys and lobby letters, hundreds came together again to share their experiences and celebrate their success.
