Who killed Sir Jack and his family? Not the KGB, surely

A murder mystery which embittered relations between Britain and France half a century ago will be revived on French television next week in a way which is likely to provoke renewed anger in both countries.

The brutal killing of a British family - Sir Jack and Lady Anne Drummond and their 10-year-old daughter Elizabeth - at their campsite in northern Provence in August 1952 was one of the great causes célèbres of the post-war years. Gaston Dominici, a 77-year-old peasant farmer, was convicted of shooting the parents and bludgeoning the child to death, but was pardoned by President Charles de Gaulle in 1960.

A two-part television film, to be broadcast in prime time on the most popular French channel on Monday and completed the following week, will allege that the Drummonds were slaughtered by a hit squad commissioned by the KGB, Russia's secret service.

The film's plot is based on a book published six years ago - and since widely rubbished - which emphasised the fact that Sir Jack was a scientist engaged in secret government work in Britain.

Both book and film allege that the Drummonds were killed by a gang of German criminals, hired by the KGB as part of a concerted Cold War campaign to eliminate leading Western scientists. Sir Jack was a nutritionist who was engaged in research into ways of combating the deliberate poisoning of food supplies.

The film, L'Affaire Dominici, made with leading French actors at a cost of €4m (£2.8m) - goes on to allege that the septuagenarian farmer was framed in a cover-up by the French government.

No other explanation of the murders is suggested in the film, despite Gaston Dominici having twice confessed to the crimes and having been identified as the killer by two of his own sons.

The film's makers insist that it should be seen as a serious contribution to the enduring debate in France over Dominici's guilt. On their website they invite viewers who are convinced by the film's version of events to support a petition launched by Dominici's grandson to have him formally cleared of the murders.

French television critics, who have been shown the film in advance, protest that TF1 has exploited harrowing real-life events to concoct a prime-time entertainment calculated to appeal to the modern taste for conspiracy theories. Telerama, a TV listings magazine, complained that the film was full of "short-cuts and extrapolations" in the service of a "dubious" theory.

To bolster its sensationalist interpretation of the Drummond murders, TF1 helped to commission a respected documentary maker, Jean-Charles Deniau, to investigate the affair.

His film, which will be shown on a different French TV channel next month, does the opposite. It pours scorn on the KGB theory and picks holes in the book on which the TV movie is based, Dominici, non coupable by William Reymond.

The documentary makers took the trouble to check with KGB archives, and former KGB officers, which M. Reymond did not. The sources and records in Moscow suggested that the Soviet security services had never heard of Jack Drummond.

Dominici was originally accused of the murders by two of his sons. One of them, Gustave, first reported the murders and admitted that he had moved the Drummonds' bodies before the police arrived. Gustave also admitted that Elizabeth Drummond was still alive when he found her. He was later given a short jail sentence for failing to help her or call for medical assistance.

Gustave and his brother Clovis said their father killed the tourists after Sir Jack Drummond, 65, found him near their tent and accused him of being a thief or peeping tom. Dominici eventually confessed, but claimed that Lady Drummond, who was 45, had agreed to have sex with him and that her husband had found them. He later retracted the confession but was convicted and sentenced to death.

In prison, he accused his son Gustave of being the true murderer. Another judicial investigation concluded that Dominici was probably guilty but his sentence was commuted to life imprisonment. He was pardoned - although not cleared - by De Gaulle in 1960 and died in 1965. He was reconciled with Gustave but not with Clovis who went to his grave insisting that his father was a murderer.