The diet divide?

But do northerners eat more?

Scientists say people living in the north of England and Scotland are more than twice as likely as their southern counterparts to develop "human mad cow disease" vCJD.

Researchers suggested this is because people in the north eat more pies and burgers - which contain comparatively low-grade meat - than those living in the south.

Are such dietary differences really so marked? And if so, why? BBC News Online tries to find out.

Facts and figures on the actual regional differences in burger and pie consumption portray a confused picture.

The CJD Surveillance Unit itself has admitted it failed to prove a link between such meat products and vCJD, because dietary analyses were "inconsistent".

Its latest annual report, for example, found that although Scotland and the north ate more meat pies, more burgers were actually eaten in the south-east.

Burgers and kebabs (average grammes per person per week 1986-7)

Scotland: 170

Northern, north-west, Yorkshire and Humberside: 166

East Midlands, east Anglia, West Midlands, south-west and Wales: 139

South-east: 205

Source: CJD Surveillance Report 2000

Data from the government's annual Dietary and Nutritional Survey of British Adults suggests little difference between north and south.

The meat and livestock commission does not give a regional breakdown of sales figures, and supermarkets were reluctant to do so.

But Taylor Nelson Sofres, a market research company which has audited fresh and frozen burger sales, said it was "categorically not true" that more were sold in the north.

Its figures suggested that a higher percentage of households in Wales, eastern England and the south-west bought burgers than did so in Yorkshire or Scotland in each of the last three years.

However, most experts are agreed that if there was a difference it would be down to money.

Professor Tim Laing, from the centre for food policy at Thames Valley University, said it was a "class issue".

Meat pies (average grammes per person per week 1986-7)

Scotland: 251

Northern, north-west, Yorkshire and Humberside: 284

East Midlands, east Anglia, West Midlands, south-west and Wales: 243

South-east: 237

Source: CJD Surveillance Report 2000

"The lower-quality meat products tend to be eaten by people on lower incomes, so in the north-south gap we might be seeing the beginnings of a class element to vCJD," he said.

Susan Price, a spokeswoman for the British Dietetic Association, agreed that money was the single most important factor driving such regional differences.

"Tradition and lifestyle are important but money makes a huge difference," she said.

She pointed out that economic factors mean not just the direct cost of food, but issues such as hours worked; access to shops; convenience and availability of fresh fruit and vegetables.

"Tradition does play a lot in it too," she said. "What you've grown up with makes a huge difference.

"People in cities, whether north or south, are likely to have been open to more influences and thus have a more varied diet."

A spokeswoman for the Vegetarian Society agreed.

vCJD cases per million people

Scotland: 2.98

Northern England: 2.66

Yorkshire and Humberside: 2.38

Wales: 1.6

South-east England: 1.4

Source: CJD Surveillance Unit

"Where there's a big farming region people are likely to eat more meat.

"Where you've got more cosmopolitan lifestyles there'll be less meat eaten, simply because people have more choice."

And she said any regional differences were becoming less and less marked with each generation.

"Traditionally the London area has been seen as more of a vegetarian zone," she said. "But more recently that's spread out and especially to other larger cities like Manchester and Liverpool.

"They have access to different cuisines and can try different ethnic foods which quite often happen to be vegetarian, like Indian and Chinese."

But professor John Ashton, north-east regional director of public health for the NHS, was sceptical as to whether there was any foundation for the claim of regional differences at all.

"The natural question is whether historically people in the north have eaten more infected food than people in the south," he said.

"But we don't know the answer to that question at the moment."