Ruth Archer: She's got us on the edge of our seats

Last night's episode of the The Archers came to an end with a scene that owed a little to Brief Encounter, another saga of a woman torn between family duty and adultery. Ruth Archer had something in her eye. Not a lump of grit from a passing steam train, of course, but a piece of ash from the Ambridge bonfire. Or so she told her newly solicitous husband David when he enquired why her eyes were watering. Avid listeners knew that Ruth was simply crying. Again. Before her was an idyllic family scene on the village green where hubby, three children and her in-laws were gathered around the festive blaze. Ahead of her: who knows?

Tomorrow night, we shall learn whether she's prepared to say goodbye to all that, leave Brookfield Farm and run off with cowman Sam into the sunset - or at least down the M40 to a hotel room in Oxford. Tomorrow also just happens to be the 15,000th edition of Britain's longest-running soap opera. Vanessa Whitburn, who has edited the programme for the past 15 years, has engineered a seasonably explosive edition to mark the event.

"We planned it three months ago to coincide with the anniversary," she says. "But the storyline about the growing relationship between Ruth and Sam has been going for over two years."

As if to prove it, she roots around on her desk in a small office off the BBC's rather cramped and crowded new studios in Birmingham's Mailbox. "Here it is," she says, holding aloft a script. "This is the scene where Sam massaged Ruth's feet after she complained about David trampling all over them in his rather clumsy attempts at salsa. It's from July, 2004." Her point is that The Archers doesn't rush these things. The editors like to keep a major storyline simmering for some time, offering listeners little tasters before allowing them to sink their teeth into the red meat. "We brought in Sam originally for solid agricultural reasons," she insists. "The management of modern dairy herds, like the one at Brookfield, requires considerable specialism. And don't forget, before she had the children, Ruth's job was to look after the herd. That was a good reason to bring them together. We've crafted scenes over the past two years where they've enjoyed working alongside each other. Only very gradually have we revved up the emotional side. If this had been television, it would have been done and dusted much quicker."

Whitburn cut her teeth on Brookside in the heady days of the late 1980s when Phil Redmond was executive producer and Jimmy McGovern was one of the writers. Script meetings could involve some passionate arguments and, on one occasion, she recalls the contents of the fruit bowl flying to and fro across the table. It was a steep learning curve that has stood her in good stead. What she learned, above all, was that storylines should always evolve from characters rather than be imposed upon them. The subsequent implosion of the Merseyside soap under the pressure of ever more implausible plots only served to underline the point. It must have been galling, then, to be summoned to appear on Radio 4's Feedback to answer charges from indignant Archers fans that Ruth has been acting out of character.

Whitburn shrugs. An editor knows that controversy is good for ratings. With around 4.6 million listeners tuning in at least once a week, The Archers is second only to the Today programme in the Radio 4 popularity stakes. The figures come out quarterly, so it's too early to say whether the Ruth-David-and-Sam saga will inspire a marked increase. But Whitburn is encouraged by the sharp upward swing in the numbers listening again on the internet, and by hits on the Archers website. "Every week we give listeners a vote on a storyline issue," she says. "Usually around 3,000 respond. But when we asked whether Ruth should go with Sam, there were over 11,000 responses and 52 per cent of them said she should."

The editor remains convinced that, because of the way the plot has been allowed to evolve over a lengthy period, Ruth's contemplation of an affair that would destroy a hitherto rock-solid marriage, devastate her children and put her livelihood at risk is perfectly conceivable.

"These big stories are talked about and argued over a lot at script meetings," she says. "There are 10 writers around that table and not one has claimed she's acting out of character. The idea that she just dumps David and rushes off in lust is not on. We're looking at a woman who's considerably torn. Yes, David loves her but he has taken her for granted for a long time. She's a woman, what's more, with a poor body image who has been tempted by the attentions of a younger man."

Why does she have a poor body image? Partly because, some years ago, Ruth underwent a mastectomy - something that Sam may or may not discover in the near future - and partly because of the re-emergence of David's glamorous former girlfriend to make her feel dowdy. Sophie has been played with vampish huskiness by Moir Leslie, who once had the very different role of Ambridge's rather earnest vicar. "As soon as Sophie made a pass at David, he reacted like the honourable man he is," Whitburn muses, "and put his wife and family first."

But is Ruth convinced of that? Not after Friday's episode, when she picked up David's mobile and heard that husky voice again. "We've had a mixture of comments on the website, some positive, some not," Whitburn goes on. "One woman said she found the story very truthful because she'd been in Ruth's position. Another said she was finding it agonising and then went on to plead with us to keep it going."

They will. Encounters in The Archers are rarely brief.