clause allowed the Ottomans to opt out of sending troops but to close the Straits to foreign warships if Russia was under threat. Egypt remained nominally under Ottoman sovereignty but was de facto independent. In 1838 in a situation similar to that of 1831, Muhammad Ali of Egypt was not happy about his lack of control and power in Syria, and he resumed military action. The Ottomans lost to the Egyptians at the Battle of Nezib on 24 June 1839 but were saved by Britain, Austria, Prussia and Russia, who signed a convention in London on 15 July 1840 that granted Muhammad Ali and his descendants the right to inherit power in Egypt in exchange for the removal of Egyptian forces from Syria and Lebanon. Moreover, Muhammad Ali had to admit a formal dependence to the Ottoman sultan. After Muhammad Ali refused to obey the requirements of the convention, the allied Anglo-Austrian fleet blockaded the Nile Delta, bombarded Beirut and captured Acre. Muhammad Ali then accepted the convention's conditions. On 13 July 1841, after the expiry of the Treaty of Unkiar Skelessi, the London Straits Convention was signed under pressure from the European countries. The new treaty deprived Russia of its right to block warships from passing into the Black Sea in case of war. Thus, the way to the Black Sea was open for British and French warships during a possible Russo-Ottoman conflict. Russian historians tend to view that history as evidence that Russia lacked aggressive plans. The Russian historian V. N. Vinogradov writes: "The signing of the documents was the result of deliberate decisions: instead of bilateral (none of the great powers recognized this Treaty of Unkiar Skelessi), the new Treaty of London was obligatory for all, it closed the Bosphorus and Dardanelles. In the absence of expansion plans, this was a sound decision". In 1838, Britain lost interest in crushing the Ottoman Empire. On the contrary, after the conclusion of the trade treaty of 1838 (see Treaty of Balta Liman), Britain received unlimited access to the markets of the Ottoman Empire, and therefore its trade interests pushed it to protect the integrity of the Ottoman Empire. In the long term, the Ottoman Empire lost the opportunity to modernize and industrialize, but in the short term, it gained the opportunity to receive the support of European powers (primarily Britain) in opposing the desire of the conquered peoples for