Read this: The immediate chain of events leading to France and the United Kingdom declaring war on Russia on 27 and 28 March 1854 came from the ambition of the French emperor Napoleon III to restore the grandeur of France. He wanted Catholic support that would come his way if he attacked Eastern Orthodoxy, as sponsored by Russia.:103 The Marquis Charles de La Valette was a zealous Catholic and a leading member of the "clerical party," which demanded French protection of the Roman Catholic rights to the holy places in Palestine. In May 1851, Napoleon appointed La Valette as his ambassador to the Porte (the Ottoman Empire).:79 The appointment was made with the intent of forcing the Ottomans to recognise France as the "sovereign authority" over the Christian population.:19 Russia disputed this attempted change in authority. Pointing to two more treaties, one in 1757 and the 1774 Treaty of Kucuk Kaynarca, the Ottomans reversed their earlier decision, renouncing the French treaty and insisting that Russia was the protector of the Orthodox Christians in the Ottoman Empire.

What individual was responsible for France and the U.K declaring war on Russia?
What is the answer? (If it cannot be answered, return "unanswerable")
Napoleon III