At which point apologies and recriminations are made, each blaming the other. Even that isn't going to escalate things to a war level. Again: dead member of the Royal Family in Irish waters, dead Ambassador and wife in Ireland, the UK embassy burned to the ground, long time suggestion/rumour of UK collusion with the largest terror attack on the island against Dublin and Monaghan... None of this triggered such an escalation, so why would a regrettable "accident" do so?I kind of like my idea of having both the Irish military and British military prepare covert spec ops strikes on the same IRA target at roughly the same time at night under cover of darkness. Only for the intel to turn out to be bad and the target is empty. Then some confusion erupts with the two raiding forces briefly thinking the other is IRA and a gunbattle erupting before someone comes to their senses.