He spent 14 years dealing with the stresses and strains of brokering multi-million pound deals in the City.

But Jan insists it is no cakewalk trying to keep a small business going, particularly in the current economic climate.

He has transformed Northfield Farm, at Cold Overton, from rundown ruins to an award-winning entity containing a thriving farmshop selling his own meat, a wine shop and a workshop for antique furniture restoration. He also operates an outlet in London, opposite Southwark Cathedral.

Jan (48) clearly has no regrets about his seismic career change: "I miss the money in the City but nothing else.

"It's a great misconception that running your own business is less stressful than doing a glamorous, well-paid, globe-trotting job.

"It's great working in the countryside but these are tough times. I have tried to diversify because that is the best way forward."

This is a busy week for Jan and his 10 full time staff. They are preparing to host their popular annual Christmas food and craft fair.

Visitors will get the chance to buy from dozens of exhibitors and tour the farm, which sits on 100 acres of farmland off the A606. Rare breed animals, such as short-legged Dexter cattle and Gloucester Old Spot pigs, are reared for their meat. The quality is not in doubt since Northfield has scooped a clutch of regional awards.

The animals are killed in local abbattoirs before their meat is prepared for sale by butchers back at the farmshop.

The farm has come a long way from the dilapidated state it was in when Jan first began living there in 1994. He was still working in the City when he moved in, after falling in love with the area, but decided to turn it into a going concern when he lost his lucrative job in the financial sector three years later.

"I was absolutely gutted and destroyed when I was made redundant," he recalled. "I came back by train and by the time I got home I had decided I was never going to apply for another job in the City.

"I already had some animals and I decided I would open up a farmshop although I had no idea how to go about it.

"The buildings needed a total overhaul. The roofs were in a dreadful state, there was a rotting railway carriage in the yard and piles of scrap metal."

From small acorns the farm has flourished. Jan's friendship with celebrity cook Clarissa Dickson Wright has helped.

They met at food events around the country and now the star of television's Two Fat Ladies and top cookery book author is a regular guest at Northfield Farm.

She champions Jan's meat wherever she goes and will once again be attending the Christmas fair this weekend.

"We have a very loyal customer base," said Jan, who is divorced but his sons Dominic (13) and 14-year-old Leo live with him.

"A good core of them are local people but some travel hundreds of miles to visit our shop."

Jan was brought up in Camden Town in London. He was born into an Irish family – his father died when he was very young and his mother ran record shops in the area.

Jan spent holidays with his grandparents in Ireland at their small farm, which is where he believes was nurtured his love of the rural way of life.

At university he read law and his aim was to become a solicitor. But he hated doing the exams and instead applied for a post with a Japanese bank in a move which was to change the course of his life.

After gaining interview advice from a friend of a friend who is now chairman of the Royal Bank of Scotland, Jan landed a very high profile job straight away.

"I knew nothing about it at the start," he recalled. "I was terrified by the amount of money involved in some of those deals. I rented a room from my mother at the time and I used to come home quaking."

Jan was a syndicate manager charged with raising large amounts of money for banks all over the world and in some cases for entire nations.

"The biggest deal I was involved in would have been worth billions of dollars," he said. "I remember one particular deal. I was one of a small team of three people raising money for Hungary. We had a very innovative method of doing it and it worked. I found out later that had we not done that deal Hungary would have gone under, which is scary."

Working long hours, sometimes through two days without sleep, and for enormous rewards, did take its toll on Jan and his colleagues.

He recalls one conference call to Japan he made in the middle of the night. "I had to get hold of this guy and it was two or three in the morning," said Jan. "I just barked down the phone to this guy's wife that I needed to speak to her husband with no apology for waking this poor lady up.

"My colleague tore me to shreds over that because I had lost my perspective. There was a lot of viciousness and rudeness in that job."

Jan foresaw a lot of the present economic problems when he was working in the financial industry.

He believes managers have not been keeping a tight enough rein on City whizzkids, who were taking bigger and braver risks with astronomical sums of money.

"I was always wary of this structure of building debt upon debt," said Jan. "The real problem now is all these grand gestures of pumping 100s of billions of pounds into the UK and the United States and yet none of it is filtering down to the grassroots.

"All this money is saving the institutions but it has all come from our pockets and yet it is not coming back into our pockets."

Jan is still recovering from the life-threatening injuries he received in a terrible tractor accident two years ago at the farm.

But he is positive about the future prospects of his business. "It is tough at present but the farmshop is strong. I've got lots of other ideas to grow the business in future."

For more details about Jan's farm and his upcoming Christmas fair, log on to www.northfieldfarm.com