Oswald Rayner, the son of Thomas Rayner, a draper, was born in Smethwick, Staffordshire, on 29th November 1888. Rayner studied modern languages at Oriel College (1907-1910) and during this period he met Felix Yusupov who was at University College. According to Richard Cullen "their friendship lasted a lifetime... one is drawn to conclude, given Yusupov's homosexual/bisexual tendencies, that he and Rayner may well have at sometime been sexually involved".
In 1910 Rayner was called to the Bar and became a barrister in the Inner Temple. According to Michael Smith, the author of Six: A History of Britain's Secret Intelligence Service (2010): "When war broke out, Rayner sought a commission in the army and with his fluency in French, Gernian and Russian was swiftly recognised as having intelligence potential. He was commissioned into the Special List and assigned to Cumming. After a brief period working at Whitehall Court, he was sent to Russia where he shared an apartment with Benet and Alley."
On 15th December 1915 he was commissioned into the British Army and sent to the British Secret Intelligence Service in Petrograd, where he served under Lieutenant-Colonel Samuel Hoare. Other members of the unit included John Scale, Cudbert Thornhill and Stephen Alley. Hoare became friendly with Vladimir Purishkevich and in November 1916 he was told about the plot to "liquidate" Gregory Rasputin. Hoare later recalled that Purishkevich's tone "was so casual that I thought his words were symptomatic of what everyone was thinking and saying rather than the expression of a definitely thought-out plan."
Giles Milton, the author of Russian Roulette: How British Spies Thwarted Lenin's Global Plot (2013) has pointed out: "At first glance, Rayner was unlikely material for espionage and subversion. He found employment as an English teacher in Finland (then an autonomous grand duchy of the Russian Empire) and taught himself Russian. He then returned to England to read Modern Languages at Oxford University. It was a move that would transform his life. Rayner's fluency in Russian, French and German did not escape official notice when he sought to join the army at the outbreak of war. Such linguistic ability was of great use in wartime."
John Scale recorded: "German intrigue was becoming more intense daily. Enemy agents were busy whispering of peace and hinting how to get it by creating disorder, rioting, etc. Things looked very black. Romania was collapsing, and Russia herself seemed weakening. The failure in communications, the shortness of foods, the sinister influence which seemed to be clogging the war machine, Rasputin the drunken debaucher influencing Russia's policy, what was to the be the end of it all?" Michael Smith, the author of Six: A History of Britain's Secret Intelligence Service (2010) has argued: "The key link between the British secret service bureau in Petrograd and the Russians plotting Rasputin's demise was Rayner through his relationship with Prince Yusupov, the leader of the Russian plotters."
Grigory Rasputin was assassinated on 29th December, 1916. Soon afterwards Prince Felix Yusupov, Vladimir Purishkevich, the leader of the monarchists in the Duma, the Grand Duke Dmitri Pavlovich Romanov, Dr. Stanislaus de Lazovert and Lieutenant Sergei Mikhailovich Sukhotin, an officer in the Preobrazhensky Regiment, confessed to being involved in the killing.
Samuel Hoare reacted angrily when Tsar Nicholas II suggested to the British ambassador, George Buchanan, that Rayner, was involved in the plot to kill Rasputin. Hoare described the story as "incredible to the point of childishness". However, Michael Smith has speculated that Rayner was at the scene of the crime: "He (Rasputin) was shot several tunes, with three different weapons, with all the evidence suggesting that Rayner fired the final fatal shot, using his personal Webley revolver."
On 7th January 1917, Stephen Alley wrote to Scale in Romania: "Although matters have not proceeded entirely to plan, our objective has clearly been achieved. Reaction to the demise of Dark Forces (a codename for Rasputin) has been well received by all, although a few awkward questions have already been asked about wider involvement. Rayner is attending to loose ends and will no doubt brief you on your return."
Richard Cullen, the author of Rasputin (2010), has argued that the assassination of Grigory Rasputin had been organised by Scale, Oswald Rayner and Stephen Alley: "Rasputin's death was calculated, brutal, violent and slow and it was orchestrated by John Scale, Stephen Alley and Oswald Rayner through the close personal relationship that existed between Rayner and Yusupov." Cullen adds: "Given the clear and supportable assertions that he (Scale) was involved in the plot to kill Rasputin, was this the reason for his absence from Petrograd?"
In 1918 Oswald Rayner was posted to Stockholm where he served under John Scale. He recruited Russian speakers to infiltrate Russia. He returned to Russia the following year and served in Vladivostok. He left the British Army in 1920 but in 1921 he was in Moscow as part of a trade mission.
In 1927 Rayner joined forces with Felix Yusupov to translate his book, Rasputin: His Malignant Influence and his Assassination, into English.
Oswald Rayner died in Botley, Oxfordshire, in 1961. After his death friends claimed Rayner told them he was with Yusupov when Rasputin was killed. In 2010 Michael Smith, the author of Six: A History of Britain's Secret Intelligence Service (2010), argued that Rayner took part in the assassination of Grigory Rasputin. This account is supported by Richard Cullen's book, Rasputin: The Role of Britain's Secret Service in his Torture and Murder (2010), who names Rayner, John Scale and Stephen Alley as being the agents involved in the killing. Giles Milton, the author of Russian Roulette: How British Spies Thwarted Lenin's Global Plot (2013), has also claimed that Rayner was the killer of Rasputin.