Security level increase

The security level in Britain has been increased to severe could this be in light of the NATO meeting that Britain is hosting in Newport Wales on Thursday and Friday. This must be an ideal target for the Islamic State or any other Islamic terrorist group that want to create devastation. A well place bomb could take out the heads of NATO and senior heads of state from an estimated 69 countries in or affiliated to NATO. Security in and around the meeting is strict, but what is there to stop a light plane packed with explosives crashing into the building holding the meeting. This is a possibility before it could be intercepted or shot down by an RAF Typhoon.