The work of spies, covert operatives and elite ‘secret soldiers’ is often hidden in the shadows but it is an important part of how Britain has fought conflicts and tackled threats at home and abroad for decades.

Find out about the agencies, military units and individuals who have fought the ‘Secret War’ – and how they address the threats of today.

MI5

Suitcase wireless transmitter seized by MI5 from captured German spies during the Second World War. This is believed to have been the set belonging to agents Werner Heinrich Walti and Karl Theo Druecke, who were captured in 1940.
© IWM (COM 1500)
Suitcase wireless transmitter seized by MI5 from captured German spies. This is believed to have been the set belonging to agents Werner Heinrich Walti and Karl Theo Druecke who landed by means of a rubber dinghy dropped from a seaplane off the Scottish coast near Portgordon on the morning of 30 September 1940.

Unlike other European powers, Britain entered the twentieth century without a secret police force. However, in 1883 the London Metropolitan Police had formed a Special Branch to combat Irish nationalist terrorism.

In spite of being under-staffed and with limited powers, its duties expanded to include the monitoring of suspicious foreign nationals and political extremists. Fears of foreign powers such as Imperial Germany and Russia gripped the nation and the British authorities ordered the creation of a security service to combat an espionage offensive.

On 1 October 1909 the War Office's Secret Service Bureau began its work. It soon developed 'home' and 'foreign' sections which became MI5 and MI6. The purpose of MI5 was to protect Britain's secrets while MI6's task was to find out the secrets of potential enemies abroad. 

The Home section was a small unit but achieved rapid success. By the outbreak of the First World War, it had assisted Special Branch in the arrest of twelve German spies. 

Carl Hans Lody was the first German spy discovered by MI5 during the First World War. German intelligence had sent Carl Lody, a naval reserve officer, to the United Kingdom in 1914 where he failed to pose as an American and began to attract suspicion. Lody was placed under surveillance which hindered his attempts to contact his controllers and on 2 October 1914, he was arrested in Ireland. Lody was found guilty of espionage and executed at the Tower of London on 6 November. 

On the morning of his execution, Lody was calm and asked an officer: 'I suppose you will not shake hands with a spy?' The officer replied: 'No, but I will shake hands with a brave man.'

At the time of his death, Lody was the first man to be executed at the Tower of London for 150 years.

MI6

Oluf Olsen, an SIS wireless operator, sits at his radio set deciphering an incoming message
© HU 68501
Oluf Olsen, an SIS wireless operator, sits at his radio set deciphering an incoming message.

MI6 is the Secret Intelligence Service and has the role of seeking out information on enemies abroad, developing contacts and gathering intelligence that helps further British interests. It was established in 1909 amid fears Germany was targeting Britain. 

During the Second World War, the service was dramatically expanded. Oluf Reed Olsen, a Norwegian who resisted the Nazis as soon as his country was invaded and was forced to flee, was recruited to MI6 to provide important intelligence about the activities of the Germans. He was parachuted back into Norway with a mission and supplies provided by MI6 - and his wartime actions earned him medals including the Distinguished Service Cross.

The work of MI6 was a closely guarded secret - its role and very existence was not officially recognized until the Intelligence Services Act of 1994 and the authorised history of the service ends in 1949. 

On the MI6 website, the service says more recent successes have gone unnoticed but that it  'is playing a major role in safeguarding the country’s people and interests'. 

Secret Communications

The Enigma was an electro-mechanical enciphering machine, ultimately produced in large quantities for the German Armed Forces. Invented in 1923, the first models were marketed for commercial company use, as a counter to industrial espionage.
© IWM (COM 22)
The Enigma was an electro-mechanical enciphering machine, ultimately produced in large quantities for the German Armed Forces. Invented in 1923, the first models were marketed for commercial company use, as a counter to industrial espionage.

Throughout history, governments and military commanders have tried to keep their communications secret by the use of codes and ciphers.

At the same time, the interception and decoding of enemy messages has been of paramount importance.

The development of cable and wireless communications made messages more secure but methods of eavesdropping soon developed creating the need for ever more sophisticate cryptography.

This Enigma Machine, like the one in this photograph, was invented in 1923 and the first models were marketed for commercial use as a counter to industrial espionage. But various German government and armed forces adopted the machine as a tool to maintain secure radio communications. 

The British Government Code and Cipher School was set up in 1939 at Bletchley Park in Buckinghamshire, and devoted large resources to breaking the various Enigma ciphers. This became known as the ULTRA programme, and was increasingly successful from 1941 onwards in penetrating German enciphered radio traffic.

Learn more about how the Enigma code was cracked and the role Bletchley Park played. 

Special Operations Executive (SOE)

Hon. Assistant Section Officer Noor Inayat Khan (code name Madeleine), George Cross, MiD, Croix de Guerre avec Etoile de Vermeil.
© IWM (HU 74868)
Hon. Assistant Section Officer Noor Inayat Khan (code name Madeleine), George Cross, MiD, Croix de Guerre avec Etoile de Vermeil. Noor Inayat Khan served as a wireless operator with F Section, Special Operations Executive.

The Special Operations Executive, created during the Second World War with instruction to ‘set Europe ablaze’.

It was created in July 1940 after the triumph of Germany’s armies on the continent and the Nazi occupation of most of Europe. It would help resistance movements and carry out subversive operations in enemy-held territory.

Operating on a global scale, SOE’s headquarters in London were supplemented by subsidiary missions on every continent.

It maintained close relations with the governments-in-exile both for recruiting purposes and to coordinate resources and objectives. 

Although secret at the time, the story of the courage and skill of agents like Violette Szabo, Adolphe Rabinovitch, Odette Sansom, George Starr and Noor Inayat Khan have become better known in recent years.

Discover more stories of SOE agents

Secret soldiers

Lieutenant Colonel Vladimir 'Popski' Peniakoff, the commander of 'Popski's Private Army', with his gunner, Corporal R Cokes, in their jeep in Italy.
© HU 1122
Lieutenant Colonel Vladimir 'Popski' Peniakoff, the commander of 'Popski's Private Army', with his gunner, Corporal R Cokes, in their jeep in Italy.

In the Second World War, technology allowed soldiers to operate behind enemy lines more effectively than in the past. Raiding parties could parachute or drive into enemy territory, and machine guns and powerful explosives gave small teams of Special Forces substantial firepower.

Vladimir Peniakoff ‘Popski’ founded and led a specialist raiding unit known as Popski’s Private Army (PPA) officially titled No.1 Demolition Squadron.

After being rejected by the Royal Navy and RAF, ‘Popski’, a Belgian of Russian ancestry by birth, joined the Libyan Arab Force (LAF) and later formed his own unit, LAF Commando.

After they were disbanded, he drew its former members together to form the PPA. It became operational in early 1943 and fought in the closing stages of the North African campaign and later in Italy.

Peniakoff was awarded the Distinguished Service Order for his part in the liberation of Ravenna but was badly injured in the fighting, losing his left hand.

Other units - such as the famous Special Air Service (SAS) - are still active and although their work is still a closely guarded secret, they have been involved in high profile missions that captured world attention. 

In 5 May 1980, the SAS stormed the Iranian embassy in London to end a siege that had started on the 30 April.

A hastily constructed model of the embassy was built so they could prepare the operation and familiarise themselves with the layout of the building.

Secret War Today

In the twenty-first century, Britain’s Intelligence and Security Services have faced new challenges, including the rise of international terrorist groups such as al-Qaeda. They have had to adapt and develop new ways of working, and become more visible within society. The public now expect them to be fully accountable for their actions.

Agents from the other states still look to uncover secrets essential to the UK’s defence or economic security. Countering this threat remains an important aspect of the Security Services’ remit. Signals intelligence remains a key part of today’s Secret War.

The Government Communications Headquarters (GCHQ) is the successor to the Second World War code-breaking establishment at Bletchley Park. The work of signals analysts today includes protecting the UK from the threat of cyber-attacks.

Special Forces also continue to play their part. In recent conflicts in Afghanistan and Iraq they have deployed alongside conventional troops.

Today’s armed forces also include specialists in intelligence-gathering and analysis, surveillance and electronic warfare.

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