My personal belief is that with the 1987 PM elections on the horizon, the combination of Thatcher's death and a bloody situation in Northern Ireland would have led to at the very least a hung election and the possibility of a Labour-SDP-Liberal Coalition, which in turn may have negotiated an end to British troops and openend up the potential for a united Ireland. Let's not forget that a majority of British people support a united Ireland.
Umm, cite?
And no, it's implausible unless you go before even the 19th century.
