Read this essay about Doctrine of Lapse !
Doctrine of lapse was the policy of Dalhousie, the then Governor General, to annexed the independent Indian States in 1848 A.D.
This doctrine was based on the idea that in case a ruler of dependent state died childless, the right of ruling over the State reverted or ‘lapsed’ to the sovereign.
This position, however, was complicated by adoption. Hindus, including Hindu rulers, attached great importance to the performance of their funeral rites by their sons and if they died without a male issue, they resorted to adoption. An adopted son was allowed to inherit private property but the political rights of ruling a State were different.
This involved the welfare of millions of people. Before 1818 A.D., the East India Company was not really sovereign over India and did not interfere in matters of succession of other Indian States.
The Company agreed to adoptions in States dependent upon itself as a matter of course between 1818 to 1834 A.D. In 1834 A.D., however, the Company came to a resolution that adoption was permissible as a matter of grace and not right and that previous permission of the Company was required for this. By 1841 A.D., the Company had resolved that adoption was not to be granted as a rule because all opportunities for the extension of British territory were to be welcomed.
By applying the doctrine of lapse, Dalhousie annexed the States of Satara (1848 A.D.), Jaipur (1849 A.D.), Sambhalpur (1849 A.D.), Bahat (1850 A.D.), Udaipur (1852 A.D.), Jhansi (1853 A.D.), and Nagpur (1854 A.D.). Annexation by lapse of ‘Karauli’ was disallowed by the Court of Directors.