British paranoid suspicion of Muslim conspiracy dates only from the 1857 Indian revolt.

Evidence

It was evidently only after the 1857 Indian revolt (largely blamed on the Muslims and the last Mughal emperor) that British officials began to subscribe to a paranoid suspicion of a Muslim threat to their dominion, and American missionaries went along with fears of a global Muslim conspiracy. — Carl W. Ernst, Islamophobia in America_ The Anatomy of…, 39