Codename Castra: the Post reporter-spy who defied the Japanese during the second world war

Archives have revealed the secret workings of a former Post reporter who became an undercover agent in the wartime fight against the invaders

Reading Time:5 minutes

A undated photo of Kay Mah (left) provided by her grandson Albert Mah. Photo: SMP Pictures

Published: 3:00am, 23 Aug 2015Updated: 2:48pm, 24 Aug 2015

Dressed in her cheongsam and with her broad face sprinkled with freckles, Kay Chinn Mah appeared to be just one of the many working women trying to find their way in the crumpled city of Hong Kong during the war years.

But Mah hid a secret identity so well that even her grandchildren only learned about it after her death in 1997 at the age of 91.

During the second world war, little did those around her know that she took on multiple disguises, collected information and ventured into dangerous places that could have got her killed by the Japanese occupiers.

An undated photo of Kay Chinn Mah (right). Photo: Albert Mah

Mah was a secret agent for the British intelligence unit MI9 during the war, travelling between Hong Kong, Macau and Guangdong province to gather information and help prisoners of war escape the Japanese.

She was, in the words of her captain, "one of his best agents".

The secret life of Mah was unveiled through archives left behind by Colonel Lindsay Ride (1898-1977), founder and commander of wartime intelligence unit British Army Aid Group.

A collection with copies of the documents compiled by his daughter Elizabeth Ride from years of research, along with some artefacts, is available for viewing at the Hong Kong Heritage Project, while the bulk of the originals are kept at the Australian War Memorial in Canberra.