Read this: Dissatisfaction with the conduct of the war was growing with the public in the UK and in other countries, aggravated by reports of fiascos, especially the humiliating defeat of the Charge of the Light Brigade at the Battle of Balaclava. On Sunday, 21 January 1855, a "snowball riot" occurred in Trafalgar Square near St. Martin-in-the-Field in which 1,500 people gathered to protest against the war by pelting buses, cabs, and pedestrians with snow balls. When the police intervened, the snowballs were directed at them. The riot was finally put down by troops and police acting with truncheons. In Parliament, Tories demanded an accounting of all soldiers, cavalry and sailors sent to the Crimea and accurate figures as to the number of casualties that had been sustained by all British armed forces in the Crimea; they were especially concerned with the Battle of Balaclava. When Parliament passed a bill to investigate by the vote of 305 to 148, Aberdeen said he had lost a vote of no confidence and resigned as prime minister on 30 January 1855. The veteran former Foreign Secretary Lord Palmerston became prime minister. Palmerston took a hard line; he wanted to expand the war, foment unrest inside the Russian Empire, and permanently reduce the Russian threat to Europe. Sweden and Prussia were willing to join the UK and France, and Russia was isolated.:400–402, 406–408

How did troops stop the riot?
What is the answer? (If it cannot be answered, return "unanswerable")
with truncheons