Hundreds of protesters have gathered in Trafalgar Square today in support of the Palestine Action group before it is expected to be banned by the government.The campaign group could be proscribed as a terrorist organisation after its members allegedly vandalised two planes at an RAF base.Protesters have been heard chanting “Stop bombing now” and “We are all Palestine Action”, as they wave Palestinian flags and hold banners which read “Defend the right to protest, drop the charges”.Home Secretary Yvette Cooper will update Parliament on the government’s response later today.Metropolitan Police Commissioner Sir Mark Rowley said he was “shocked and frustrated” that the demonstration supporting the “organised extremist criminal group” was going ahead.