New Delhi, Jul 3 (IANS): Former prime minister Atal Bihari Vajpayee had said that the "mistake" in Gujarat was the reason for the National Democratic Alliance's defeat in the 2004 general election, former RAW chief A.S.Dulat has said.

In an interview conducted by Karan Thapar and telecast on India Today TV channel on Thursday, Dulat said Vajpayee admitted Gujarat was a mistake. "You could see the sadness in his (Vajpayee's) eyes," he said.

"Gujarat mein humse kuch galti ho gayi (We committed some mistake in Gujarat)," Dulat quoted Vajpayee as saying.

Dulat, whose book, "Kashmir: The Vajpayee Years", is slated to be released shortly, said BJP leader L.K. Advani, who was the deputy prime minister in the Atal Bihari Vajpayee government, was not happy with the way the then principal secretary Brijesh Mishra was given importance by Vajpayee.

"Brijesh Mishra virtually ran the government. He was cool, composed and was the only boss. He had a very sharp mind. Advani felt the principal secretary was more important than the deputy PM and this was the main issue between Advani and Vajpayee," Dulat said.