What if in 1981, a rogue communist groups splits from the Provisional IRA and receives funding from the Soviet Union and other communist states through covert means.
This communist group later comes out stating their goal is to spread communism to a sovereign Ireland and starts targeting Parliament, British icons like Big Ben, and US military bases in the UK along with the US embassy.
How would this effect the Thatcher administration and cold war politics, assuming their KGB funding is discovered?