Prime Minister William Pitt the Younger was alarmed at Russian expansion in Crimea in the 1780s at the expense of his Ottoman ally. He tried to get Parliamentary support for reversing it. In peace talks with the Ottomans, Russia refused to return the key Ochakov fortress. Pitt wanted to threaten military retaliation. However Russia's ambassador Semyon Vorontsov organised Pitt's enemies and launched a public opinion campaign. Pitt won the vote so narrowly that he gave up and Vorontsov secured a renewal of the commercial treaty between Britain and Russia.