Judith Holder takes exception when people accuse her of being a Southerner. She'll point out that she was born in Birmingham, went to university in Leeds and now lives in Northumberland.

"In a way being a Brummie gives you an inside view of the North-South divide," she says.

It's an insight she's put to good use in the new BBC2 series It's Grim Up North, which comes from the same people that gave us Grumpy Old Men and Grumpy Old Women.

This latest might be subtitled Grumpy Old Northerners because the aim is to redress the balance and point out that the South's assumptions about the North aren't correct.

It reveals, for instance, that Londoners fart more than people in other parts of the country. Not that the experts have been measuring air quality, merely that Southerners buy more flatulence remedies. Well, you know what they say about an ill wind.

Stuart Prebble, who "invented" Grumpy Old Men, came up with the idea of a programme about the North-South divide that was pro-North and anti-South. "He lives in Kingston-on-Thames, so he could hardly do it," says Holder, who's head of features at North-East based production company Liberty Bell.

"I suppose I'd always noticed the divide and got increasingly fed up that it was always me who was going down to meetings in London, that it was me going to get on the train.

"Then you'd go to a meeting and you have your coat on and people would say, 'you've come all that way, is it cold up there?'. The weather is always so South-centric."

The series pits North against South with the likes of Jenny Eclair, Stephen Tompkinson, Shobna Gulati, Justin Moorhouse and Stuart Maconie representing the Northern celebrities doing verbal battle with Southern softies including Brian Sewell, Michael Winner and Simon Heffer.

Holder says that while the sub-text is serious, she hopes the approach of the series and the book doesn't come across as dreary. "I do feel quite strongly it was our turn and say the North-East isn't as you think at all," she adds.

"With Grumpy Old Men and Grumpy Old Women, it was time for middle-age to have a voice and not be dominated by youth culture. I wanted to do something that's not Viz but mainstream, that's more pro-North."

There are statistics - other than those concerning flatulence - to prove it's not all grim up North. The weather statistics between Hartlepool and Cannes are interchangeable; people in Newcastle buy twice as much champagne as Londoners; and the sexiest accents are Scottish, Irish and Geordie.

Carol Smillie, who's Scottish, says Southerners pretend not to understand people because of their Northern accents. Moorhouse complains that you can't get a cheese sandwich down South as "it's all panini this and panini that". Maconie says that a Southern idea of a pie is a fish pie.

"There's a lot of fun about food and the fact that there's a world lard shortage because the Eastern Europeans are in Europe now and use it for cooking. Someone was actually selling lard on eBay."

One of the first questions that Holder had to consider was where is the North? "Officially, it's Watford Gap, so we went around Watford looking for the gap," she says. She didn't find it because Watford Gap is further North, well away from Watford.

"What I decided to say was that anywhere within the M25 is South. Cornwall, Devon, places that are forgotten or ignored in the same way as the honorary North," she says.

Film director Michael Winner had his own idea about where the North begins - "it starts North of Hyde Park, it starts at Oxford Street, anything North of Oxford Street is ridiculous".

Plummy-voiced art critic Brian Sewell wonders what to do with the string of mill towns "that seem to run one end to the other in Lancashire". His answer may seem extreme: "I think the most one could hope for is that we have another plague, another bout of Russian flu, that depletes the population by 20 million and then we can demolish all those places," he says.

Yorkshireman Alan Titchmarsh admits being saddened that his children don't have a Northern accent. "It would be nice if they just had those flat vowels. But the most depressing thing now is that they've both got a slight Australian twang because they watch Neighbours," he adds.

As part of her mission to challenge Northern stereotypes, Holder took to the streets down South and up North to compare the friendliness of people. Now, with the programme ready for screening, she's off on holiday to the South. The South of France, to be precise.

l It's Grim Up North begins on BBC2 on Friday at 10pm. The book of the series is published by BBC Books on Thursday, price £9.99.