Sarah Waldron of the Campaign Against the Arms Trade claimed that the event would welcome "some of the most authoritarian regimes in the world".
"The deals done here fuel death, injury, fear and repression - yet instead of banning it, the Government helps make it happen.
"We are here to resist it, to stand in solidarity with the people facing the deadly consequences of its weapons and do what we can to stop this obscene event continuing."
More top news
Police are hunting for the owners of this jewellery which they believe is stolen
Police investigating the murder of a 20-year-old man in East London have named him as Moosakhan Nasiri.
18 year old Shafiq Smith was charged early this morning with the murder of Omid Saidy