Tran Hiep spent his 51st birthday alone in a notorious detention centre in Ho Chi Minh City after his sudden arrest last month

• Get our breaking news email, free app or daily news podcast

Tran Hiep spent his 51st birthday alone in a notorious detention centre in Vietnam’s Ho Chi Minh City after his sudden arrest last month.

The Melbourne-based Vietnamese-Australian democracy campaigner hasn’t been heard from since mid-September when Vietnamese authorities detained him for alleged terrorism and forging identity documents.