In September 1806, the British government pressured Sultan Selim III to expel Sebastiani, declare war on France, cede the Danubian Principalities to Russia, and surrender the Ottoman fleet, together with the forts on the Dardanelles, to the Royal Navy. After Selim's rejection of the ultimatum, a British squadron under Vice Admiral John Thomas Duckworth entered the Dardanelles on 19 February 1807 and destroyed an Ottoman naval force in the Sea of Marmara, and anchored opposite Constantinople. With French assistance the Ottomans erected powerful batteries and strengthened their fortifications.[2] The British warships were cannonaded suffering the loss of two ships. Duckworth made the decision to withdraw to the Mediterranean on 3 March 1807.
On 16 March 1807, 6,000 British troops embarked for Alexandria in Ottoman Egypt, which they captured in August. Governor Muhammad Ali mounted effective counter-attacks and a lack of supplies forced the British to withdraw. The Ottoman Empire had little military support from France due to the war with Russia; Napoleon failed to secure Russia's compliance with the armistice agreement of 1807 with Britain, which was now at war with both France and Russia.
