the mounted admiralty arch , which joins trafalgar square with the mall , and called for others to join them .
it is not clear what their protest is attempting to highlight , as a garbled message posted on facebook by the group simply calls for ` christmas lights ... any and all radical/revolutionary messages ' that banners bearing messages such as ` better squat than let homes rot ' and ` respect existence or expect resistance ' and another , who asked not to be named .