We have the same thing in Germany, the domestic intelligence services keeping tabs on MPs. Of course Germany has a rich tradition in this kind of behaviour.

That being said we are on a slippery slop when the State thinks it needs to protect itself from its elected members of parliament.

Like that time when the King was a Nazi spy. That was awkward. http://www.lrb.co.uk/v10/n16/paul-foot/the-great-times-they-... . The position of the Sinn Fein MPs is awkward as well.

Peter Hain complained about the security forces holding a file on him due to anti-apartheit campaigning: http://www.theguardian.com/commentisfree/2015/mar/25/special...

And now we have Jeremy Corbyn being openly denounced as a "threat to national security". This has got Russia Today laughing at us, pointing out that we'd be condemning the same language if used by a regime we didn't like.

MI5 themselves beg to differ[3] (though they don't address Wallace's allegations directly, it seems.)

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.

  1: https://en.wikipedia.org/wiki/Colin_Wallace
  2: https://en.wikipedia.org/wiki/Harold_Wilson_conspiracy_theories
  3: https://www.mi5.gov.uk/home/about-us/who-we-are/mi5-history/the-cold-war/the-wilson-plot.html
  4: https://en.wikipedia.org/wiki/A_Very_British_Coup