That already happened a while ago (though MI5, not GCHQ), according to this guy[1] and several other &quot;theorists&quot; (viz. [2])<p>MI5 themselves beg to differ[3] (though they don&#x27;t address Wallace&#x27;s allegations directly, it seems.)<p>And the whole idea, with a fictional PM, was made into a novel by eminently monitorable ex-MP Chris Mullin[4] and then a miniseries.<p><pre><code>  1: https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Colin_Wallace
  2: https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Harold_Wilson_conspiracy_theories
  3: https:&#x2F;&#x2F;www.mi5.gov.uk&#x2F;home&#x2F;about-us&#x2F;who-we-are&#x2F;mi5-history&#x2F;the-cold-war&#x2F;the-wilson-plot.html
  4: https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;A_Very_British_Coup</code></pre>