A quiet Twickenham street was swiftly evacuated and cordoned off in February this year as police carefully explored a house previously occupied by a shy and retiring elderly woman.

Richmond and Twickenham Times:

Properly dressed: Eileen Burgoyne in her armed forces picture

There had long been whispers about the polite but reclusive lady who lived at number 26, and the discovery of firearms and ammunition at the house seemed to confirm the neighbour’s suspicions. Had their elderly neighbour really been a World War II and Cold War era spook?

Eileen Burgoyne, who quietly lived out her retirement in Grimwood Road for more than 20 years, until her death in 2014, had worked for the intelligence services immediately after the Second World War. She was posted overseas for the Combined Services Detailed Interrogation Centre (CSDIC), which operated interrogation centres around the world.

Among the cache of weapons discovered at her home by a team of builders on February 16 was a Sten submachine gun, an austere British 9mm weapon used throughout the Second World War, known for its simple design and cheap production costs. The gun was found in full working order.

Richmond and Twickenham Times:

Still working: This weapon caused the evacuation

Ms Burgoyne’s cousin, Georgina Wood, had no idea of her relative’s existence, let alone the fascinating life she had led, but upon her death she was sent many of Ms Burgoyne’s belongings.

Some of the correspondence she received included letters and telegrams from the War Office, photos of Hamburg devastated by Allied bombs, an invitation to a German hotel from a Lieutenant Colonel from 1945, pay-slips from the Woman’s Royal Army Corps and freedom passes from the Danish Allied Committee.

What is left of Ms Burgoyne’s personal file reveals she had two periods of service, 1945-47 and 1950-53, and that she was a talented linguist, having studied French and Spanish at college in Manchester.

The police spokesman who accessed her file said there was clearly a lot of detail missing about what exactly she was doing for the CSDIC and there was even reference to files having been destroyed.

Among the effects sent to Ms Wood is an invitation to Kaiserhof Hotel in Bad Pyrmont, just one hour’s drive away from the controversial interrogation centre at Bad Nenndorf, opened by the CSDIC shortly after the war for the interrogation of Nazi prisoners.

Richmond and Twickenham Times:

Fascinating: Even some family were unaware of Ms Burgoyne's colourful past

The centre’s remit was later expanded to include people suspected of spying for the Soviet Union, but it was closed in 1947 amid accusations of the maltreatment of detainees.

Ian Cobain, a journalist who investigated alleged torture in interrogation centres including Bad Nennforf and Camp 020 on Ham Common for his book Cruel Britannia, said Ms Burgoyne may have worked as a typist or translator during the interrogation of prisoners.

He said: "Interrogations would have been seen as a man’s job but they sometimes had women in the room typing up what was said.

"There was a lot of admin that would have needed to be done but if she was a linguist then she may well have been a translator."

One of Ms Burgoyne’s neighbours, Richard Markell, said it was quite well known that she had been a spy, and the weapons may have been kept at the home as a form of protection during her retirement, or as souvenirs of a fascinating career.

Richmond and Twickenham Times:

Personal effects: Including some pictures of devastation in mainland Europe

Exactly what work Ms Burgoyne did during and after the war we may never know, but what we can be certain of is this quiet old lady led a fascinating life in the thick of one of the most important chapters in modern history.