I've come across what seems to be an interesting piece of British history which also appears to have involved the QE2.
It is alleged that during the Wilson (Labour) Governments of the 1960's & 1970's, there where far right elements conspiring to bring the government down. It was also rumoured that sometime in the 1970's Lord Mountbatten was approached to lead a new government following the overthrow.
QE2's association arises from a theory that she was to have been requisitioned by the plotters in order to detain members of the then cabinet. In July 1975 Sir Basil Smallpeice (who had left Cunard some years earlier) was seemingly approached to attend a meeting about the ship. Recognising that he (Sir Basil) had no influence over the ship he was dismissed. Although the incident was reported to Sir Michael Cary (Permanent Secretary at the Minsitry of Defence) nothing further happened.
I've tried to find if there is anything further in the www but have only managed to turn up these (rather detailed) commentaries on the alleged coup, but disappointngly neither mentions the ship. Apparently, there are official papers released that provide further detail.
Further Details 1 -
Further Details 2