Don't expect a nice sit-down and a cuppa at the new breed of farmhouse tearooms. Paul Vallely visits the Lake District caffs where old-fashioned fare is now the fastest food in the North

There have been Dawsons at Greystone House since it was built in 1752. The date, carved in a fine hand into the great stone lintel above the front door, reveals as much. But four years ago the foot and mouth disease epidemic - in which an estimated 20 million animals were slaughtered - almost put an end to that.

There have been Dawsons at Greystone House since it was built in 1752. The date, carved in a fine hand into the great stone lintel above the front door, reveals as much. But four years ago the foot and mouth disease epidemic - in which an estimated 20 million animals were slaughtered - almost put an end to that.

That there are Dawsons still farming in the rolling Lakeland countryside between Keswick and Penrith is in no small measure due to the ingenuity and determination of Marjorie Dawson, who has come up with another wheeze to find additional ways of bringing extra cash to the economy of the farm. She has dreamt up the idea of Britain's first drive-through olde-worlde tea shoppe.

"It started five years ago," she said, sitting in the oak-beamed loft-house tearoom at the centre of the organic farm which is now a thriving business for herself and her husband. "I was working in a field - harrowing, which is very boring, just up and down, up and down - so I was watching the road and noticed how many cars went past. I thought if I could sell a cup of tea to one in 10 of them, I could make a bob or two."

But the plan she hatched - to build a tearoom in one of their fields by the local dual carriageway - ran immediately into red-tape problems. The planners required her to commission a traffic survey. "That alone would have cost £10,000. It was crazy money." So the Dawsons converted a barn in the farmyard and decided that if the tearoom wasn't allowed to go to the cars then they would have to organise things the other way round.

Last week, John and Marjorie had their first drive-through customer. Admittedly, it was their son John, in one of the family tractors, who had called on his mobile to order a tray to be brought into the yard bearing a pot of Earl Grey and a slice of carrot cake.

But the publicity on local television has brought paying customers in his wake. When I arrived, the couple were doing a tasting of their own sausages on a barbecue, but within minutes the phone rang. Gordon, the farm's full-time butcher, came out bearing a cordless phone: "Today's first drive-thru," he said. John grabbed a pen and pad and began to scribble. "A brie and grape sandwich. Five minutes," he shouted as he marched into the kitchen.

Strictly speaking, it was not a drive-thru so much as a takeaway. Five minutes later Helen Brass, who runs the poultry farm up the road, pulled into the yard. "I'll eat it back in the office," she said. "It's a godsend, this service," she added before dashing away.

This is only one of a number of farm tearooms which are going drive-through. The Dawsons have even set up a website to promote the scheme, which they have dubbed Old MacDonald's, in an attempt to combine the notion of fast food and farm fare.

"It is all a bit tongue in cheek," said another of the participants, Alison Park of Low Sizergh Barn farm shop and tearoom just off the busy A591 between Kendal and the M6. Both Marjorie and Alison's tearooms are within minutes of a motorway junction. "Places like ours are really about slow food not fast food. It's about stopping and savouring the good things of life. On the other hand, if people are in a hurry we'll adapt to meet their needs."

There is a serious point to all this. When the Dawsons and the Parks families started out, their farms supported the shop. Now it's the other way round. A quiet revolution is occurring in the British countryside, which could change the face of the rural economy and landscape. Farmers now make more money from tourism than from traditional farming.

Traditional farming yields between £300 and £400 a year from each 10 acres of land; by contrast, the average turnover of the farmers who have switched was £243,875, according to a study by North West Farm Tourism.

In 2001, when foot and mouth struck, the Dawsons' farm was declared a "dangerous contact", which means that any farm within 5km had animals infected. All the Dawsons' livestock had to be destroyed. To make ends meet, John Dawson got a job for the agriculture ministry, rounding up animals for slaughter.

"He was astonished at the number of sheep in the area," his wife recalls, "and he realised that the way we looked after animals would never be economic. The way forward was ranching." That meant looking after the beasts in a minimal way. "It was low input, that meant letting sick animals die; they'd never sit and feed orphan lambs with a bottle like we do. Our proper animal-welfare method could never pay.

"We were in a global market and there was no way we could compete on price with South American beef or New Zealand lamb. So we had to go for quality. We made the decision to go organic." Yet even that was not enough, which is where the farm shop and tearoom came in.

Further south, in the lower reaches of the Lake District, Alison Park and her family had seen the writing on the wall even earlier. They moved from a farm in Lancashire to Low Sizergh Farm in 1980 with the intention of building up a herd of Holstein Friesian dairy cows. The start of milk quotas in 1984 put paid to that.

They looked for additional sources of income - livery stables, pick-your-own strawberries - before alighting on the idea of a farm shop after people buying strawberries asked if they sold cream or ice-cream. Her parents toured lots of farm stores before settling on Chatsworth - the Harrods of farm shops - as a model in 1991. "Success for us has been partly because there are so many different elements of the business," Alison says. "A working farm, dairy products from the milk we sell to local cheese-makers, a farm shop where we sell the cheeses and much else, a tearoom, then a fashion department and a crafts gallery. They all feed each other all the time."

Alison Parks is clearly driven by the entire project. She walks around the converted 17th-century Westmorland-stone barn, enthusiastically revealing the stories behind the produce she sells.

The butter is by Susan Forrester, a farmer's wife who couldn't bear to see milk thrown away, so started to make butter in her Kenwood mixer. It has an really old-fashioned, strong taste. The jams and jellies are by Jane Moggs. Her rationale even extends to the tea and coffee, which are all Fairtrade products. All of this gives some clue as to why Low Sizergh was both Farm Retailer of the Year in 2005 and Best Tea Shop 2004-05.

"We take as many products from different sources as possible," says Marjorie. "It means a lot more paperwork. But the range of things is what makes the shop what it is."

Being an alternative network to that of the supermarkets, who have squeezed farmers badly in the past, is clearly an important motivation to Marjorie Dawson and Alison Park. So is creating jobs to help stop young people leaving the countryside. When it was just a farm, Greystone House provided work for just two people; now it has six full-time and 14 part-time employees.

"It's every bit as hard work as before," says Marjorie's husband, John. "But I'm at home more, I enjoy life more and I get to meet lots of people. The customers are genuinely happy at our success. They seem to feel part of it."

His wife laughs. "We knew we'd succeeded," she says,"when estate agents started to advertise houses locally by saying "not far from a very good village shop". But, with the passing trade of the M6 barely two miles off it may well be that their reputation will spread well beyond the local.