Andrew Graham-Dixon may look harmless with his chinos and his Hugh Grant hair, but don't be fooled: the man's an assassin (BBC Four, Secret Lives of the Artists: Constable in Love, Tuesday 11 January, 9pm). Calm down. There's no reason to be alarmed - unless you are an art historian, in which case I hope you have made a will. No matter whether you are in a gallery, your office or at home, Andrew will get you with an interpretation of a famous work that will take your breath away, literally. His aim is to eliminate all other art historians on television, and the body count grows each week. Make the most of Matthew Collings and Waldemar Januszczak, they may not be around for much longer.
Disposing of rivals is only half the job. The other consists of presenting yourself as a man who cannot countenance violence even in a painting. Andrew is urbane, plausible, a charming fellow for whom murder would appear to be a breach of good manners. In many ways, he is reminiscent of Patricia Highsmith's cultured serial killer, Tom Ripley. Both have an interest in art and both haven't been caught. But Ripley sometimes feels a pang of regret for his victims.
A little of Andrew's ruthlessness showed through as he drove through sunny Suffolk in a coupé. Britart, he said, with a smile that sent the temperature plummeting, "did not have much time for John Constable, but he was more revolutionary than any other artist in the last 40 or 50 years". He then accelerated off before anyone could argue with him. As if they would.
A study of Constable is about as close as Andrew will get to the law, or the law will get to him. There was an element of a police report in the opening remarks. "In the winter of 1813, a painter of a sunlit English countryside was hiding in the streets of London near St James', hoping to see the woman he loved." The painter was Constable and the woman was Maria Bicknell, whom he met in 1801 when he was 24 and she was 12. Dusk seemed to be the appropriate setting for this revelation, although Andrew, a blurry figure behind railings, assured us that nothing untoward occurred.
Maria's family were opposed to her marrying Constable. He came from trade, hoped to live by brush and canvas and had little money. Hardly a match for the daughter of an important London lawyer and solicitor to the Admiralty. But even if those obstacles could be overcome, there was still the small matter of Constable's caricature of Revd Dr Durand Rhudde, Maria's wealthy grandfather, rector of East Bergholt, a man in the mould of Dr Johnson who would not shirk from correcting the Deity if he thought Him in error.
Richard Constable, the painter's great-great grandson, said he used to think that Maria wasn't worthy of his famous relative because she wasn't prepared to defy her father to marry him. He and Andrew were sitting in a delightfully old-fashioned sitting room full of character, one of the few homes to have escaped a makeover from the Grand Designs team. "Did they cheat?" asked Andrew, a rare linguistic slip. He recovered almost immediately. "I mean, did they have relations?" There was pause. "That is a very delicate way of putting it," Richard said quietly. "They would never even have considered to behave that way before marriage." His outrage at the question clearly taking its toll on his syntax.
Was he aware, you wondered, of Constable's reputation with the ladies? Conal Shields relayed an anecdote of the painter subduing a local maiden with the words: "God brought me into this world to do a job and you are going to help me do it." A sentence that left you lamenting the depleted rhetoric of courtship in the early 19th century. Of course, Constable could only have been asking her to carry his easel rather than to ease his desire, but we will never know. As for Conal, Andrew probably dispatched him after the programme. A shame. He seemed such a nice man.
Andrew tried to find the views that Constable painted. But who can see through another's eyes? He spent a good part of the hour either with his head in the clouds or with his feet on the ground. It made no difference. Whether he was up a church tower or perched at the edge of a wood, the sweet scenes had gone, even before Constable's paint had dried. He captured a moment. It's still there in his art, but it's vanished from nature. Andrew proclaimed that Maria gave an expressive quality to Constable's painting. That's not an original idea, although Andrew seemed to think it was. Still, no one tells it like he does. If not being an art historian can't save me, perhaps flattery - no, homage - can.