Britain and France declared war on Russia after it attacked Turkey.
Britain and France mounted an expedition to invade Russia and landed in the Crimea. The 11th Hussars took part in the war from the start. The 10th Hussars were in India at the time, and their tour was cut short when in 1855 they were ordered to reinforce the British in the Crimea. They were too late to take part in the main battles and were only involved in skirmishes before the campaign ended.