Golitsyn claimed that Rt Hon. Harold Wilson (then Prime Minister of the United Kingdom) was a KGB informer and an agent of influence. This encouraged pre-existing conspiracy theories within the British security services concerning Wilson. During his time as President of the Board of Trade in the late 1940s, Wilson had been on trade missions to Russia and cultivated a friendship with Anastas Mikoyan and Vyacheslav Molotov. He continued these relationships when Labour went into Opposition, and according to material from the Mitrokhin Archive, his insights into British politics were passed to and highly rated by the KGB. An "agent development file" was opened in the hope of recruiting Harold Wilson, and the codename "OLDING" was given to him. However "the development did not come to fruition," according to the KGB file records. Golitsyn also accused the KGB of poisoning Hugh Gaitskell, Wilson's predecessor as leader of the Labour Party, in order for Wilson to take over the party. Gaitskell died after a sudden attack of lupus erythematosus, an autoimmune disorder, in 1963. Golitsyn's claims about Wilson were believed in particular by the senior MI5 counterintelligence officer Peter Wright. Although Wilson was repeatedly investigated by MI5 and cleared of this accusation, individuals within the service continued to believe that he was an agent of the KGB, and this belief played a part in the coup plots against him.
John Smith, ironically for someone who was on the Gaitskellite wing of the party, has become an iconic figure for Labour's left-wing and centre since his death, because of his perceived traditionalist approach and the contrasts between his leadership and those of Neil Kinnock and Tony Blair. This perception has also arisen as many on the Labour left have argued that the party had swung too far to the right under Blair's leadership. Smith, though he introduced OMOV, refused to amend Clause IV because he thought it was irrelevant. (It was eventually amended on 29 April 1995.)
John Smith's biographer, Mark Stuart, claimed that Smith could have won Labour a Parliamentary victory in 1997 on a similar scale to that achieved by Tony Blair due to the combination of the Black Wednesday debacle and ongoing Conservative divisions over Europe between 1992 and 1997; however, Stuart argues that the lack of a Blair effect would have meant that the Conservative Party would have held slightly over 200 seats in the House of Commons, leaving the Conservatives in a position similar to that of Labour in 1983 than to the actual Conservative result in 1997. The sense that Smith's untimely death cheated him of the premiership may well have contributed to the nostalgia for his leadership by the Labour left; a common sentiment is that Smith was the "best Prime Minister we never had".