They were dropped behind enemy lines into Nazi occupied Poland, to start the fight to regain their homeland.

It was 80 years ago today (Monday) that an elite group of Polish Home Army parachutists stepped up with courage and determination. Audley End House was their secret agent 'finishing school'.

English Heritage, which cares for Audley End House, wants to hear from family members with memories of the Cichociemni - the Silent Unseen. The special operations paratroopers were all volunteers and were trained in covert operations, sabotage and intelligence-gathering.

The 527 people who used Audley End House as their final training base before they were deployed left behind few visible signs they had ever been there.

A scrap of graffiti is still in the coal gallery candle store, there are torn labels in the cellar where guns and ammunition were stored, and there are remnants of a timetable from the former briefing room.

Nails in bedroom walls mark the spot where pictures were hung and insulators for telephone wires were stuck in tree trunks. A memorial to the Cichociemni stands in the grounds.

Saffron Walden Reporter: Memorial to Polish members of the Special Operations Executive who lost their lives during World War TwoMemorial to Polish members of the Special Operations Executive who lost their lives during World War Two (Image: © Historic England)

Saffron Walden Reporter: Cichociemni agents play football at Audley EndCichociemni agents play football at Audley End (Image: From the collection of the Polish Underground Movement Study Trust - London, colourised by English Heritage.)

Saffron Walden Reporter: Józef Zabielski with Gen Kazimierz Sosnkowski at Audley End HouseJózef Zabielski with Gen Kazimierz Sosnkowski at Audley End House (Image: Janusz Zabielski)

Arkady Rzegocki, Polish ambassador to the UK, said: "The 80th anniversary of the first mission of the Silent Unseen – Cichociemni is an important date in the history of Poland, Polish special operations forces and Polish-British relations.

"On the night of February 15-16, 1941, the first group of Polish Home Army parachutists, who were all volunteers, were dropped into occupied Poland, the first such airdrop behind German lines, offering a glimmer of hope to the besieged homeland that help was coming.

"With skills they developed in such places as Audley End, home to the Polish section of the Special Operations Executive, Cichociemni landed under cover of darkness to support the fight against the enemy, becoming the pride of the Polish Republic.

"Their brave and heroic service inspired GROM, one of Poland's premier special missions units, to adopt their name and continue their traditions. Let their name and sacrifice never be forgotten. Thank you to all who keep the memory of Cichociemni alive."

Andrew Hann, English Heritage historian, said: “It is a privilege to play a small part as a caretaker of this incredible story where individuals acted so selflessly to risk everything in the defence of their homeland against Nazi occupation.

"We are honoured that Audley End has come to hold such as special place for Poles as the spiritual home of wartime resistance and we’re committed to helping share that story in the hope that the sacrifices of these extraordinary people go on to inspire future generations.

“We’d love to hear from the public who have a connection or story to share about the Cichociemni.

"We’re particularly interested in hearing from those who may remember hearing bangs in the night, or seeing troops crossing fields in the darkness.

"Perhaps unsurprisingly, given that they were highly trained to be both ‘silent and unseen’ they left little obvious trace.”

Anyone with memories to share should email press@english-heritage.org.uk

Saffron Walden Reporter: Audley End HouseAudley End House (Image: Source: English Heritage Photo Library - Picture Reference: N071842)