The Irish Fright was a mass panic that took place in England in December 1688, during the Glorious Revolution. It accompanied the final days of King James II's regime after his initially thwarted attempt to flee into exile in France. Troops of the Jacobite Irish Army were stationed in England to prop up James II's authority but were widely detested by the predominately Protestant population of England.
Rumours began to circulate in mid-December that the Irish soldiers were preparing to carry out a campaign of massacre and pillage against the English population in revenge for James's overthrow. False reports of the Irish burning English towns and massacring inhabitants spread the panic rapidly from London to at least nineteen English counties, whose inhabitants formed armed militias to guard against supposed Irish marauders. The panic subsided after a few days. It was never determined who was responsible for sparking it, though contemporaries suspected that it may have been the work of Orangist sympathisers seeking to further discredit James II.
James II inherited an army in Ireland on his accession in 1685. At the time it amounted to 8,238 men, all of whom were supposed to be Protestants and were required to provide certificates confirming that they received the Church of England's sacrament twice a year. (Some Catholics did nonetheless manage to join the force during the reign of the Catholic James II.) By 1688 its strength had grown to 8,938, of which 2,820 were sent to England in September 1688 to reinforce the English Army against the expected invasion by William, Prince of Orange, James II's son-in-law who had been invited to enter the country by English politicians opposed to James II's rule. Many of them were stationed in Portsmouth, where they became objects of suspicion and fear. A newsletter of early October 1688 reported that Portsmouth's inhabitants were making "great complaints of the rude Irish who have caused many families to leave that place, having committed many robberies".
Their presence in England further stoked long-standing fears that Irish or Catholic forces were poised to launch an anti-Protestant uprising. In Staffordshire in 1641, Protestants were reportedly so afraid that their Catholic neighbours would attack them that they "durst not go to Church unarmed". Later that same year, a panic in the towns of Ludlow and Bewdley led the inhabitants of both towns to mobilise on the night of 19–20 November, watching for what they believed was the arrival of insurgent Catholics. In 1681 the House of Lords announced the existence of "a horrid and treasonable Plot and Conspiracy, contrived and carried on by those of the Popish Religion in Irseland, for massacring the English, and subverting the Protestant Religion, and the ancient established Government of that Kingdom."