In 1986, Armstrong was the key witness for the British Government as it sought to suppress the publication of
Spycatcher, in which it alleged its author,
Peter Wright, had attempted to disclose confidential information. At the time Wright was a retired high-ranking member of
MI5 and was about to publish his book in Australia. The evidence given by Armstrong was widely ridiculed by the British press for its absurd ambiguity and seemingly deceptive nature. Wright's lawyer,
Malcolm Turnbull, who later became the
Prime Minister of Australia, was ultimately successful in lifting the publication ban. Turnbull described Armstrong as being like "
Sir Humphrey Appleby" from
Yes Minister and said "If he is an honest man, then he appears rather like a well-educated mushroom". He is credited with bringing the phrase "
economical with the truth" into popular usage, after he used it during the
Spycatcher trial in 1986; his use of the phrase was subsequently included in the
Oxford Dictionary of Quotations. == Later life ==