Video: Protesters target Thames Diamond Jubilee Pageant Anti-monarchy campaign group Republic chose the day to voice their opposition to monarchy and to call for a republican constitution for Britain, mounting a protest near Tower Bridge. The protesters were boo-ed by a few members of the pageant crowd who were enjoying watching the 1,000 boat flotilla pass. One protester said he was there to demonstrate against the "unaccountable power of the Crown and the constitutional power that it still has."