In May 1857, with the Indian Mutiny reaching boiling point, Sir Henry Lawrence summoned from their homes two sets of pensioners, one of sepoys and one of artillerymen, to defend the Lucknow British Residency. Lawrence would not clear the mosques surrounding the 60-acre site, which provided cover for rebel sharpshooters and artillery - 'spare the holy places' - and was almost immediately killed by a shell.

Thus began one of the most dramatic episodes in the history of the British Empire: truly a Victorian epic. Hundreds of women and children cowered in the complex as the bombs and bullets flew. The first relief attempt led by Maj Gen Havelock failed. The tens of thousands of besiegers undermined the defences and food was running out. With massive loss of life and after 87 days, the relief force reached the Residency - to become besieged themselves for another six weeks. The 64-year-old Sir Colin Campbell led the second relief column through the rebels, the 4th Punjab Infantry Regiment emptying their muskets and resorting to the bayonet. After 148 days under siege, retreat was the only option and the whole garrison moved to Cawnpore.

The following March, Lucknow was retaken. Victorian military history expert William Wright returns to primary sources to tell the extraordinary story.