When Wilkie Collins wrote 'The Woman in White' in 1859 it was an instant hit. Jasper Rees argues that his writing entirely chimes in with the needs of a modern television-watching audience. Indeed, the Victorian novelist could well have been the first

TV scriptwriter.

That he died half a century before John Logie Baird discovered television is a mere detail. The two novels on which Wilkie Collins' reputation as a prototype television writer rests are commonly agreed to have more or less kicked off the genres that are the bread-and-butter of the small screen. The Woman in White is the first thriller; The Moonstone the first detective yarn with, in Sergeant Cuff, the original maverick detective; and both were originally published in serial form.

They plainly value Collins's scriptwriting talent at BBC Drama. Last Christmas brought an adaptation of The Moonstone, and this Christmas it's the turn of The Woman in White. No matter that the BBC's last attempt at the novel, a five-part serial, is only 15 years old - so recent, in fact, that Ian Richardson reprises his role as the nerve-shredded invalid Frederick Fairlie. The new version has been sumptuously filmed by Tim Fywell, who, as the director of several menacing Barbara Vine adaptations, could not have a more appropriate pedigree.

Both Kevin Elyot, who adapted The Moonstone, and David Pirie, who scripted The Woman in White, agree that Collins the television writer has a head- start over other Victorian novelists. "Because he wrote The Moonstone under the influence of laudanum," says Elyot, "I do think he creates a very visual paranoid world."

"He's a more filmic writer than Dickens," says Pirie, "because he embeds his ideas into plots, whereas in Dickens they seem to sit on the surface."

It's not necessarily the case, though, that Collins's page-turners entirely chime in with the patterns of television entertainment. Pirie's adaptation of The Woman in White has been ruthless with Collins's generous and occasionally flabby narrative. Foreshortenings were also imposed on last Christmas's The Moonstone. And, contrary to either original template, the two television versions make only a cursory nod to the serial format. Like The Moonstone, The Woman in White goes out as a two-parter, structurally limiting the ration of cliffhangers to just the one.

It is hard to overstate the first impact of The Woman in White. Collins was 35, with a decade of unremarked backwork behind him. His novel was serialised between November 1859 and August 1860, in both his friend Dickens's new rag, All the Year Round, which had just announced itself with A Tale of Two Cities, and Harper's magazine in America. The novel was extraordinarily popular: dances, bonnets, cloaks and scents were named after it, in a kind of decorous precedent to the pop troupes' endorsements for crisp packets. Gladstone famously cancelled a theatre engagement to finish it.

Readers immediately thrilled to the tale of Sir Percival Glyde's efforts to accede to the fortune of his young wife, Laura Fairlie. But as absorbing as the plot was Collins's way with richly fascinating characters. Glyde's accomplice is the far more cunning Count Fosco, a charismatically obese Italian who travels with a menagerie of pets, while contrary to all literary precedents, Laura's ugly half-sister Marian turns out to be as capable an opponent.

Pirie was already at home with The Woman in White's theme of planned uxoricide. His CV also boasts last Christmas's ITV thriller Element of Doubt, in which Nigel Havers coldly plots to bump off his wife Gina McKee for money. "When I first proposed The Woman in White some years ago," he says, "I thought it would be a serial, but if you do a serial you're falling into a trap. Yes, the novel was written as a serial but a TV serial is entirely different. It doesn't always translate properly. It was just as well to concentrate the thing and pull together the central thread."

This is partly a matter of convenience - in this version Fosco is denied the satisfying but not hugely relevant comeuppance Collins gave him in the book (leaving the door ajar for The Woman in White II). But there's also a need to smooth out the wilder coincidences that formed part of the staple diet of the novel's first readership. Collins's recipe for a successful narrative was "Make 'em laugh, make 'em cry, make 'em wait." But he also made 'em swallow some implausible plot twists. Collins eventually provides an explanation for the likeness between heiress Laura Fairlie and illegitimate Anne Catherick that underpins the Glyde-Fosco plot. But the spooky opening scene on Hampstead Heath in which the art teacher Walter Hartright first sights the haunting woman in white has been transplanted up to Cumberland, where, in the novel, he encounters her for a second time. "I love the Hampstead Heath scene," says Pirie, "but we couldn't really have bought the coincidence that somehow he meets her by chance on the Heath and then happens to be going hundreds of miles North to the one house to which she has an intimate relation."

Collins provides another difficult tripwire for those adapting him. Both novels are told in the dossier format via a diaries, letters, testaments written by the characters. In one thrilling transtextual coup, we discover that Fosco, like us, has been reading Marian's diary. They are literary documents, in other words, which tend to be so much dead weight in a drama. When Pirie took his idea to Central, they mooted moving the novel to 1929, which would have killed off the feverish epistolary activity that drives the plot. "I pointed out that the invention of the telephone would make The Woman in White an impossible plot. The whole notion of imprisonment - of not being able to communicate - is the central conceit: literally every man in Britain who was married was running a private prison."

Letter-writing is even more integral to The Moonstone. "Some of the information I managed to extract from the letters and dramatise," says Elyot. "Some letters I kept in. Letters, like phone calls in contemporary drama, can work. It's just the way that they're done. I don't see a problem per se.

Though there was nothing deeply wrong with The Moonstone beyond a certain floweriness in both the casting and direction, Elyot says the adaptation could have been better.

"The version that was transmitted was not quite true to my original vision, which got lost along the way. It was budgeted inaccurately and this caused all sorts of problems. A lot of the time the buck kept coming back to me to edit the script in order to accommodate more cuts." The lesson of these two adaptations is that Collins's plots may be overweight, but some respond more favourably than others to the austere measures that television tries to impose on them.

If you're in the mood for implausible coincidences, by the way, try this one. Long before he adapted The Moonstone, Kevin Elyot appeared in the 1982 BBC series of The Woman in White as the footman who pushes Richardson's Frederick Fairlie around in a wheelchair. If you put that in a television drama, no one would believe you.

'The Woman in White' begins on Sunday, 8.50pm, on BBC1 and concludes 9.30pm the following night.