Stop the War (StW) have a track record of denying a platform to Syrian voices when they hold events about Syria. As I've said before, this is like an organisation holding repeated #BlackLivesMatter events with all-white panels. As far as I know, StW have only come close to having Syrian speakers twice, both in 2013: first they gave platform to a Baathist and then they invited a Lebanese-French nun (Mother Agnes) who they said was Syrian - which backfired when no one would sit on the same platform as her. The Syria Solidarity Movement have written about a whole sequence of instances when they have denied a platform to Syrians at events about Syria.
I've already linked to Paulo Canning's "Have Stop the War Coalition finally jumped the shark?" and
James Bloodworth's "Stop the War refuse to listen to Syrians during debate…on Syria", which describe a recent parliamentary meeting to which StW invited no Syrians and at which chair Diane Abbott effectively shut down their voices.
Paulo's piece was reblogged elsewhere, but he has since added a series of updates, which are important. Here are some extracts, with my emphases and a couple of hyperlinks added: