Pakistan gave uranium enrichment technology to North Korea in return for missiles, says the biography of the slain PPP leader authored by her close friend Shyam Bhatia.

The 'enrichment for missiles' barter took place in 1993, says the book Goodbye Shahzadi whose author cites the information revealed by Bhutto herself during a conversation with him.

As secret services of India, Russia and some western countries were closely monitoring every move on Pakistan's military research, Bhutto had decided to herself carry the sensitive material to Pyongyang to avoid detection, the book says.

"As she (Bhutto) was due to visit North Korea at the end of 1993, she was asked and readily agreed to carry critical nuclear data on her person and hand it over on arrival in Pyongyang," the book claims.

"...before leaving Islamabad, she shopped for an overcoat with the 'deepest possible pockets' into which she transferred CDs containing the scientific data about uranium enrichment that the North Koreans wanted," it says.

"She (Benazir) did not tell me how many CDs were given to her to carry, or who they were given to when she arrived in Pyongyang, but she implied with a glint in her eye that she had acted as a two-way courier, bringing North Korea's missile information on CDs back with her on the return journey," the author writes.

Bhutto got back not only the designs but also disassembled parts of an entire Nodong missile for Pakistani scientists to study part by part in the security of their own laboratories, the book suggests.

Later, Pakistani and North Korean engineers are said to have worked together as joint advisers to develop Iran's rockets, it claims.

Bhatia, who cites his close association with Bhutto since their Oxford days, quotes the former Pakistan Prime Minister as saying : "You know I cannot take credit for our nuclear programme, that goes to my father, but I am the mother of the missile programme."

Later, on the record, Bhutto merely said that the Nodong was strictly a cash deal.

"I took it up with (North Korean leader) Kim Il Sung ... he agreed ... and it was cash; they needed money and so it was done for cash," the author quotes Bhutto as having said.