A forlorn hope is a band of soldiers or other combatants chosen to take the vanguard in a military operation, such as a suicidal assault through the kill zone of a defended position, or the first men to climb a scaling ladder against a defended fortification, or a rearguard, to be expended to save a retreating army, where the risk of casualties is high. Such men were volunteers motivated by the promise of reward or promotion, or men under punishment offered pardon for their offenses, if they survived.

Field Marshal Colin Campbell, 1st Baron Clyde,, was a British Army officer. After serving in the Peninsular War and the War of 1812, he commanded the 98th Regiment of Foot during the First Opium War and then commanded a brigade during the Second Anglo-Sikh War. He went on to command the Highland Brigade at the Battle of Alma and with his "thin red line of Highlanders" he repulsed the Russian attack on Balaclava during the Crimean War. At an early stage of the Indian Mutiny, he became Commander-in-Chief, India and, in that role, he relieved and then evacuated Lucknow and, after attacking and decisively defeating Tatya Tope at the Second Battle of Cawnpore, captured Lucknow again. Whilst still commander-in-chief he dealt with the "White Mutiny" among East India Company troops, and organised the army sent east in the Second Opium War.