The Guardian's security editor, Richard Norton-Taylor, will be answering users' questions and comments about last week's attacks at 1pm (BST) on Thursday on our talkboards. You can post messages on the talkthread now and join the discussion live at 1pm.
Comments are closed on this blog post as Richard won't be looking at it. If you have trouble using the talkboards, you can email questions to userhelp@guardian.co.uk.
Topics you might want to ask Richard about include: How did the terrorists evade the detection of Britain's security services? What, if any, was the level of foreign involvement? How did the suspects, who seem to have come from unexceptional backgrounds and families long-established in Britain, become so radicalised? Could there be more such attacks?
