During the Second Russo-Turkish War, Britain delivered an ultimatum to Russia demanding that Russian forces under the command of Potemkin withdraw from Ochakov, which Potemkin had recently secured, and establish a peace agreement with the Ottomans, or Britain, Prussia and Poland-Lithuania would intervene in the war in support of the Ottomans. In our timeline, the British Government ultimately withdrew the ultimatum, and such a war never came about - but what if Russia rejected the ultimatum before it was withdrawn, and an Anglo-Russian War erupted in 1790? How long would such a war last? Who would win? What would become of the French Revolutionary Wars?