A judge has acquitted eight protesters who blockaded the entrance to an arms fair, accepting their argument that they acted to stop illegal weapons trading.

The eight were charged after blocking the entrance to the huge Defense and Security Equipment International trade show in London in September. They denied guilt.

Defense witnesses told the trial at London's Stratford Magistrates' Court that there was evidence weapons had been sold illegally at the fair in previous years to countries accused of human rights violations, including Bahrain and Saudi Arabia.

District Judge Angus Hamilton acquitted the defendants Friday. In a written ruling published Monday, he said the defendants were "perfectly sincere" in concluding that illegal weapons were being sold and "that their intervention was necessary to seek to prevent this."