Five of the best spy infiltrations from history

From the 1500s to the modern-day, here are some of the past's most intriguing tales of espionage.

Britain's intelligence services issued a warning over an alleged spy infiltration within the Houses of Parliament earlier this week.

The suspected subversion was revealed on Thursday in a letter to MPs from Commons' Speaker Sir Lindsey Hoyle in which he said a person had been 'engaged in political interference activities on behalf of the Chinese Communist Party.'

It was also suspected that the son of the alleged agent was working for a Member of Parliament until just a few hours before the Speaker's letter was issued.

​​​​​​​The revelation of such a well-placed human intelligence source chimes with incidents from the Cold War era and raises questions about China's ability to frustrate or manipulate high profile decision-makers in rival countries worldwide.

But how does this infiltration compare to other famous and infamous spy operations in the past?

Here, we examine five occasions when spy craft altered the course of history.

Sir Anthony Blunt was one of Britain's most notable art historians and Surveyor of the Queen's Pictures. Picture: Alamy.

The spy in Buckingham Palace

Sir Anthony Blunt was the Queen's personal surveyor of art and one of Britain's most respected art historians.

In 1979, then Prime Minister Margaret Thatcher announced Blunt had confessed to being a Soviet spy and had passed on extremely sensitive information to the Russians throughout the Second World War.   

He was considered the so-called 'fourth man', a member of the Cambridge Spy Ring recruited by the Soviet Union in the 1930s.

Following the war, Blunt was sent abroad on behalf of King George VI to retrieve key items and artwork that the Royal Family did not have an automatic right to. These tasks were perhaps most notably covered in season three of the Netflix drama The Crown.

Following Thatcher's statement confirming Blunt as a Russian spy, a man who had infiltrated the highest of British institutions, the ageing former agent was stripped of his knighthood. It was further revealed he had been granted immunity from prosecution some 15 years earlier by then Prime Minister Sir Alec Douglas-Home.

In explaining his betrayal, Blunt would later quote EM Forster, saying: "If asked to choose between betraying his friend and betraying his country, he hoped he would have the guts to betray his country," referencing his Cambridge University friends and co-Soviet spies. Blunt died in London at the age of 75 in 1983.


'Spy's Hysterical Wife Almost Compromised D-Day'
Juan Pujol - codename: Agent GARBO.

Spaniard Juan Pujol was a German agent who, in 1941, had approached the Nazis and offered to engage in espionage against the British in London.

The Germans instructed Pujol to construct a network of fifth columnists who they could later use to advance their plans in the war against the allies.

However, unbeknown to the Germans, Pujol was secretly a British double-agent codenamed GARBO. Instead of aiding Germany to wage war in Europe, he frustrated it.

A significant achievement came in 1944 when, in advance of D-Day, GARBO provided comprehensive plans about the allies' forthcoming military campaign. But the details he revealed were false, as were the network of agents he had apparently constructed to help gather that intelligence.

Thanks to GARBO's infiltration of the German intelligence service, Hitler and his forces were caught completely unawares on D-Day. His work helped win the war.

MI5 acknowledges the double-agent's work to this day. On its website, it says:

In December 1944, Pujol was awarded an MBE presented by the Security Service's Director General, Sir David Petrie, in recognition of his services. Pujol eventually moved to Venezuela, where he lived in relative anonymity. He died in Caracas in 1988.

A wireless message sent to the Germans by GARBO which helped the Allies surprise Hitler on D-Day. Picture: Alamy.

Iraqi spy's infiltration of ISIS

In 2014, Capt. Harith al-Sudani, a member of Iraq's counterterrorism intelligence unit, the Falcon Intelligence Cell, infiltrated the membership of the world's deadliest terror organisation, ISIS.

In the 16 months of his undercover operation, the secret agent secured enormous successes, including the foiling of 30 planned car-bombing attacks. The 36-year-old was, according to the New York Times, "perhaps Iraq's greatest spy, one of a few in the world to have infiltrated the upper reaches of the Islamic State."

In 2016, Capt. Sudani's cover became compromised, placing the man's life in immediate danger of a barbaric death. In the face of terrible risk, the Iraqi agent decided to continue his essential undercover work, unaware of the fate that was about to befall him.

ISIS, having grown suspicious, bugged his vehicle and gained irrefutable evidence that their man was, in fact, a spy. Capt. Sudani was imprisoned and, it is suspected, beheaded. His body has never been recovered.

The Execution of Mary Queen of Scots

Queen Mary was just six days old when her father died in 1542, placing her on the throne of Scotland.

Mary Queen of Scots, as she was known, grew into adulthood believing she had a legitimate claim to the English crown, placing her in a diplomatic confrontation with England's reigning Queen Elizabeth I.

The matter was made worse by Mary's Roman Catholicism, at odds with Elizabeth's Protestantism, a contentious issue for two centuries of English history.

After spending her childhood in France, Mary's return to Scotland prompted fears among Elizabeth's council that war might break out between the two countries. In those circumstances, Mary would seek to depose England of her Queen.

There were significant worries that Mary would manoeuvre to have Elizabeth assassinated to take the English crown for herself and her successors.

To counter those risks, Elizabeth became the first monarch to initiate a network of secret agents. And it was their work that eventually led to the unfurling of a plot to harm the English Queen.

Before this, Elizabeth had permitted Mary to live in England in a part exile, part imprisonment arrangement following a tumultuous period in Scotland that saw her reign end.

But while granting her a home, Elizabeth instructed her intelligence officials to watch the Scot closely.  

In a recent book, Secret Royals: Spying and the Crown from Victoria to Diana, authors Richard J. Aldrich and Rory Cormac revealed just how successful the Queen's spies were and the extent to which Mary was prepared to cause the Queen harm:

"Walsingham uncovered the plot and this time offensively used it to entrap, and finally remove, Mary. He created, and secretly controlled, a channel of communication to and from the unsuspecting Mary. She thought her incriminating letters were secure but Walsingham's agents, who had infiltrated her circle and helped establish the channel, ensured they were decoded and made their way back to him.

"The deciphered messages implicating Mary piled up. Walsingham turned his evidence over to Cecil, a more impeccably respectable advisor and better placed to present the case against Mary to the Queen. On 8 October 1586, faced with overwhelming evidence, Elizabeth gave her agreement to 'authorise them to use their discretion respecting the manner of first communicating with the Queen of Scots; also in respect to any private interview with her if she should require it'. Mary was arrested and awaited trial for treason."

The situation was intense. Mary's ambition and belief were proven, as was her intention to engage in treacherous activities. And it was all thanks to the work of the Queen's spies. Mary was tried and beheaded.

Double agent Dmitri Polyakov

For 25 years, Dmitri Polyakov was deemed a "legend" of spycraft, working covertly for the CIA as an ultra-deep mole within the Soviet Union.

Thanks to his infiltration, the US was kept abreast of Soviet military planning and remained intelligent to Russian weaponry advances. Experts say he singlehandedly kept the Cold War from spilling over. Among the information he provided, details of the growing rift between the Soviet Union and China paved the way for President Nixon to begin diplomatic relations with the Chinese in 1972.

In 1984, CIA spies monitoring the Soviet press spotted a recipe for Coot – a traditional Eastern European dish – which caused grave concern among American intelligence chiefs. Polyakov had placed the recipe in the media to indicate that he needed to make emergency contact with his US agent handlers. Soon after, the agent went silent, and his dialogue with the USA ceased.

Two years later, Polyakov was arrested in the Soviet Union. In 1988, he was tried for treason and subsequently executed.