Up to 160 mourners have attended the funeral service of Dr David Kelly, including his widow, Janice (58), eldest daughter Sian (32) and twins Ellen and Rachel (30).
Britain's deputy prime minister, Mr John Prescott, and Lord Hutton - the man who will lead the inquiry into Dr Kelly's death - also attended St Mary's Church in Longworth, Oxfordshire.
The 13th century church overlooks the spot where Dr Kelly killed himself three weeks ago.
Dr Kelly's death came after he was named as the source of BBC claims that intelligence on Iraq's weapons capability was "sexed up" by spin doctors.
Mrs Kelly met Lord Hutton before a preliminary sitting of the Hutton Inquiry was held last week. She requested that today's service should be private.
The church bells began to toll as the hearse bearing the scientist's coffin - covered by a tribute of white flowers - arrived.
It was followed by Dr Kelly's family, who walked behind the coffin as it was carried into the church. Dr Kelly's family asked for the service to be as private as possible and restricted media access.
The Order of Service and the text of the vicar's sermon are not expected to be released.
Outside there was one photographer, one reporter and a camera crew to operating a pooled facility.
The village of Longworth was sealed off by police as well as the road outside Dr Kelly's house in the village of Southmoor, around two miles away.
Following the funeral, Dr Kelly was laid to rest in the graveyard of St Mary's, in the shadow of the north side of the 13th century building.
The service was thought to have elements of the Baha'i religion, to which Dr Kelly converted four years ago while working in the United States.
His family were said to have chosen Baha'i prayers from a selection made by followers at his local Baha'i centre.
PA