A UN weapons inspector who resigned over the issue of weapons of mass destruction joined campaigners at a North Yorkshire military base.
There have been 4 July protests at the base since 1980
Scott Ritter addressed activists at the annual 4 July protests outside the US intelligence and surveillance base at Menwith Hill, near Harrogate.
Mr Ritter then gave a talk at Leeds Civic Hall on Monday evening.
Protesters from the Campaign for the Accountability of American Bases said they "will not be silenced".
Joint co-ordinator Lindis Percy said: "We will be making the links between the outrage of poverty in Africa and the hypocrisy of the billions and billions of dollars that are being spent on military weaponry and war fighting world wide.
"Menwith Hill is crucial in the American missile defence programme. This is something that George W Bush and Tony Blair keep very quiet about.
"However, we will not be silent or be silenced."