London, April 9 (IANS): The Archbishop of Canterbury has announced that a DNA test result revealing the identity of his real father has come as a "complete surprise".

The Most Reverend Justin Welby, 60, has discovered that he is the son of former British prime minister Winston Churchill's last private secretary, the late Anthony Montague Browne, BBC reported on Saturday.

He had believed his father was whiskey salesman Gavin Welby, who died in 1977.

His mother, Lady Williams of Elvel, has confirmed she had a "liaison" with Browne just before she got married to Gavin Welby in 1955.

Williams, whose marriage to Gavin Welby broke up in 1958, had worked as secretary to Churchill during his final spell as prime minister.

She said the news had come as an "almost unbelievable shock", and although her memory of the time was patchy, she recalled sleeping with Browne after "a large amount of alcohol on both sides".

The Daily Telegraph reported that Archbishop Welby, the most senior cleric in the worldwide Anglican communion, decided to take a DNA test after it approached him with research it had carried out into his family's background.

It reported mouth swabs were compared with hair samples from a hairbrush kept by Browne's widow and showed a 99.9779 percent probability they were father and son.