The British did not steal the Koh-i-Noor diamond. It was acquired by the
British East India Company in 1849, following the Second Anglo-Sikh War.
The Treaty of Lahore, which was signed at the end of the war,
required the Maharaja of Lahore, Duleep Singh, to cede the diamond to the British.
Some people have argued that the British acquisition of the Koh-i-Noor was a
form of theft, as Duleep Singh was only a child at the time and
was not in a position to make an informed decision about the diamond's future.
However, the Treaty of Lahore was a legally binding agreement, and the
British were within their rights to demand the Koh-i-Noor as part of the spoils of war.