In 1852, Commodore Lambert was dispatched to Burma by Lord Dalhousie over a number of minor issues related to the Treaty of Yandabo between the countries. The Burmese immediately made concessions including the removal of a governor whom the British made their casus belli. Lambert, described by Dalhousie in a private letter as the "combustible commodore", eventually provoked a naval confrontation in extremely questionable circumstances by blockading the port of Rangoon and thus started the Second Anglo-Burmese War which ended in the British annexing the province of Pegu and renaming it Lower Burma. In the British parliament Richard Cobden made a scathing attack on Dalhousie for despatching a naval commodore to negotiate (gunboat diplomacy) and for raising the initial demand for compensation of £1000 to 10 times that amount, published in his pamphlet "How Wars are got up in India: the Origin of the Burmese War". He also criticised Dalhousie for choosing Lambert over Archibald Bogle, an army officer and company commissioner of much more experience in Burmese social and diplomatic affairs. Dalhousie denied that Lambert was the cause.
The first substantial blow of the Second Burmese War was struck by the British on April 5, 1852, when the port of Martaban was taken. Rangoon was occupied on the 12th and the Shwedagon Pagoda on the 14th, after heavy fighting, when the Burmese army retired northwards. Bassein was seized on May 19, and Pegu was taken on June 3, after some sharp fighting round the Shwemawdaw Pagoda. During the rainy season the approval of the East India Company's court of directors and of the British government was obtained as to the annexation of the lower portion of the Irrawaddy River Valley, including Prome.
Lord Dalhousie visited Rangoon in July and August, and discussed the whole situation with the civil, military and naval authorities. He decided that to dictate terms to the Court of Ava by marching to the capital was not how the war should be conducted unless complete annexation of the kingdom was contemplated and this was deemed unachievable in both military and economic terms for the time being. As a consequence General Godwin, who bitterly resented having to deal with the Royal Navy under the command of Lambert, a mere commodore, after the death earlier of Rear Admiral Charles Austen, the brother of the writer Jane Austen, occupied Prome on October 9 encountering only slight resistance from the Burmese forces under the command of the ineffectual son of the great general Maha Bandula who was killed in the First Burmese War. Early in December Lord Dalhousie informed King Pagan that the province of Pegu would henceforth form part of the British dominions.
The proclamation of annexation was issued on January 20 1853, and thus the Second Burmese War was brought to an end without any treaty being signed. The war resulted in a revolution in Amarapura although it was then still called the Court of Ava, with Pagan Min (1846–1852) being overthrown by his half brother Mindon Min (1853-1878). Mindon immediately sued for peace but the two Italian priests he sent to negotiate found the British 50 miles farther north at Myedè with a rich belt of the Ningyan teak forests already staked out within their territory and presented as a fait accompli. No treaty was ever signed although trade resumed between British Burma and the Kingdom of Ava until fresh hostilities broke out in 1885.