An armed Metropolitan Police officer has been forced to step in and shut down a group of tourists who had been heckling a British soldier standing guard in London.A video posted on social media site TikTok appears to show a group of American tourists filming the soldier and shouting out names, hoping to get a reaction from the Household Cavalry trooper who was standing guard.Throughout the encounter, the cavalryman was calm and professional, remaining at ease with his sword in hand and giving no reaction to their jeers.