Dr Morag Kerr explores the details of baggage transfers in a 250-page book, concluding that the bomb originated at Heathrow, not in Malta, and that the man convicted of the atrocity, Abdelbaset Ali Mohmed al Megrahi was not involved.
"Heathrow was indeed the scene of the crime," she claims, as the 25th anniversary of the bombing approaches this month. "There is irrefutable evidence the bomb was in a suitcase seen at Heathrow before the feeder flight from Frankfurt landed.
"Megrahi was nowhere near the place and could not possibly have had anything to do with it.
"The Lockerbie investigation was horrifically bungled thanks to stupidity, carelessness and tunnel vision. The police made a fatal error...and eliminated Heathrow on a false assumption."
Ms Kerr, a member of the Justice for Megrahi Committee which wants a new independent inquiry into the conviction of the only man found guilty of the blast, based her findings on statements, reports and photographs, some previously not publicly available.
Her book Adequately Explained by Stupidity? Lockerbie, Luggage And Lies, includes a foreward by Terry Waite, the former special envoy to the Archbishop of Canterbury, who was held captive in Beirut from 1987 to 1991.
Ms Kerr, 60, from Peeblesshire, disputes the prosecution's case that Megrahi and another Libyan, Al Amin Khalifa Fhimah, placed the bomb in a Samsonite suitcase and put it into the baggage system at Malta's Luqa Airport as unaccompanied luggage.
The prosecution case was that the suitcase then went on an Air Malta flight to Frankfurt, was transferred to a feeder flight to Heathrow and was subsequently loaded on to Pan Am 103, where it exploded over the Scottish town on December 21, 1988, killing 270 people.
Ms Kerr questions the chain of events agreed by a special Scottish court sitting at Camp Zeist in the Netherlands, and claims to have pinpointed a mystery suitcase on the aircraft at the location of the blast.
She said: "We convicted Megrahi on evidence that wouldn't support the issuing of a parking ticket, imprisoned him 1800 miles from his home and family and turned him into an international hate figure while he was in the terminal stages of aggressive prostate cancer."
The prosecution successfully linked Megrahi with the bombing by fragments of clothing that were found wrapped around the remnants of the device.
He was identified by Maltese businessman Anthony Gauci, who claimed he sold items of clothing and an umbrella to a Libyan man who looked "a lot" like Megrahi three weeks before the bombing.
Megrahi was found guilty in 2000 and sentenced to 27 years, while his co-accused Fhimah was cleared. Megrahi was released from Greenock Prison in 2009 on compassionate grounds after being diagnosed with terminal prostate cancer. He died last year.
Last night a Crown Office spokesman dismissed Ms Kerr's claims. He said: "The theory set out in this book was rejected as speculation by the court.
"The only appropriate forum for the determination of guilt or innocence is the criminal court, and Mr Megrahi was convicted unanimously by three senior judges. His conviction was upheld unanimously by five judges, in an Appeal Court presided over by the Lord Justice General, Scotland's most senior judge.
"As the investigation remains live, it would not be appropriate to offer further comment."