Sir William Mark Tully is the former Bureau Chief of the BBC, New Delhi. He worked with the BBC for a period of 30 years before resigning in July 1994. He held the position of Chief of Bureau, BBC, Delhi, for 20 years. He has received awards and written books. He is a member of the Oriental Club.

Tully was made an Officer of the Order of the British Empire in 1985 and was awarded the Padma Shree in 1992. He was knighted in the New Year Honours 2002, receiving a KBE, and in 2005 he received the Padma Bhushan. BAFTA in 1985 for lifelong achievement. He has conferred the coveted RedInk Lifetime Achievement Award of the Mumbai Press Club.

Tully's first book on India Amritsar: Mrs Gandhi's Last Battle (1985) was co-authored with his colleague in BBC Delhi, Satish Jacob; the book dealt with the events leading up to Operation Blue Star, Indian military action carried out between 1 and 8 June 1984 to remove militant religious leader Jarnail Singh Bhindranwale and his followers from the buildings of the Harmandir Sahib (Golden Temple) complex in Amritsar, Punjab.

His next book Raj to Rajiv: 40 Years of Indian Independence was written with Zareer Masani, and was based on a BBC radio series of the same name. In the US, this book was published under the title India: Forty Years of Independence.

Tully's No Full Stops in India (1988), a collection of journalistic essays, was published in the US as The Defeat of a Congress-man. The Independent wrote that "Tully's profound knowledge and sympathy unravels a few of the more bewildering and enchanting mysteries of the subcontinent".

Tully's only work of fiction, The Heart of India, was published in 1995.

In 2002 came India in Slow Motion, written in collaboration with Gillian Wright and published by Viking. Reviewing the book in The Observer, Michael Holland wrote of Tully that "Few foreigners manage to get under the skin of the world's biggest democracy the way he does, and fewer still can write about it with the clarity and insight he brings to all his work”.

Tully later wrote India's Unending Journey (2008) and India: The Road Ahead (2011), published in India under the title Non-Stop India.