"We never bring potential investors to Northern Ireland in the month of July," says Mr Brendan Mullan, chief executive of Investment Belfast.

Investment Belfast is dedicated to promoting investment opportunities in the North's largest city. Like many other business leaders in Northern Ireland, Mr Mullan is resigned to the fact that July is a no-go area for business.

Despite the fact that Investment Belfast has seen a rise in the number of inquires from potential investors, a single incident of unrest in the North is enough, according to the organisation, to set alarm bells ringing for new inward investors.

Widespread unrest is the equivalent to setting off the sprinklers, according to economic advisers who say the slightest hint of civil unrest and potential investors' enthusiasm for Northern Ireland is not merely dampened but submerged.

According to Mr Nigel Smyth, Northern Ireland director of the Confederation of British Industry in the North, it is not just potential investors' confidence that is affected by sporadic outbreaks of violence.

"The political situation in the North, particularly the Drumcree situation, now means that we have an 11month economic calendar. July is out of bounds for customers, for suppliers, for towns, for businesses," he says.

The July fortnight, which includes the bank holiday on the 12th, is still observed by many businesses in the North as the annual holiday period.

The majority of manufacturing, building and service industries close for two weeks, akin to the Parisians and their approach to business in the month of August.

But while France may strictly celebrate the holiday period, the run-up to the July fortnight in Northern Ireland has become a spectre that most businesses have come to dread.

As July 12th draws near, the day when the Orange Order takes to the roads and streets of Northern Ireland to celebrate the Battle of the Boyne, the atmosphere inevitably grows more tense and the climax in the past six years has been the stand-off at Drumcree.

For businesses and companies in the North, Drumcree now equates to potentially lost production time, possible lost orders and an inescapable loss of customer confidence in Northern Ireland-based businesses.

A new book published last month outlines for the first time that the Drumcree standoff, according to economists, has cost Northern Ireland £1 billion sterling (€1.7 billion) over the past six years.

The authors of Drumcree, The Orange Order's Last Stand, outline various costs associated with the stand-off each year, from additional policing which is estimated to have cost £50 million since 1995, to criminal damage claims totalling £166 million, to criminal injury claims which have amounted to £174 million.

According to the authors, Mr Chris Ryder and Mr Vincent Kearney, in the most recent financial year the Roads Service had to pay out £250,000 to repair roads damaged by burning vehicles and other disturbances arising from Drumcree.

They say that when all of this is added together, including the cost of lost investment, jobs, visitors and contracts, it amounts to £1 billion.

"Over the period, that equates to about £50,000 for each of the 2,000 citizens of Portadown, three Protestants for every Catholic," the authors write in the book.

Many companies across the North have suffered from the periods of unrest that July inevitably heralds but no more so than in Portadown, which has become the unwilling host for the Drumcree stand-off every year.

The area is home to some of the North's most successful companies including Galen Holdings, Ulster Carpet Mills and Moy Park.

According to Mr Mike Mills, chief executive of Ulster Carpet Mills, many companies find that their competitors try to capitalise on the Drumcree situation.

"Our competitors jump on this bandwagon every year, they have become so tuned to it that it is now as predictable as the tides. "They tell our customers and their customers that they should not risk placing orders with companies in the Portadown area because they paint a picture that if there is trouble they may not get delivery of that order," he said.

"The fact is that industry in Portadown has to deal with this myth. It is just part of the myths of Drumcree, which get worldwide circulation by the media, and customers respond not to facts but to images, and imagine that the worst can happen.

"If you are the owners of a luxury hotel and you need your carpets for a certain date to open and someone tells you `oh, there might be trouble in Portadown', what are you to think?" Mr Mills says. He says the fact is the company, which is based on the Garvaghy Road, takes two weeks' holiday during the July fortnight, which allows them to carry out "fundamental maintenance".

"While our Portadown plant is closed our facilities in South Africa and Australia are still working away producing orders, and vice versa, when they are then closed for maintenance our plant in Portadown is working away supplying to various parts of the world.

"Far from being detrimental to our business, it is to our advantage to be located in Portadown because we have great people who have been instrumental in our success as a company.

"We have a workforce from both the Protestant and Catholic communities, and there is a cordial, friendly team spirit which all of us delight in. I suppose there is a certain irony for some people in that, considering where we are located," Mr Mills adds. But he says that, despite the fact that companies in Portadown are good at dealing with the myth of Drumcree, he believes the situation has cost businesses dear in the area.

"I think it has probably cost industry a great number of jobs, it has probably cost us business and cost some companies orders.

"The great tragedy is that the people who live on Garvaghy Road are good people, the people in the Orange Order are good people but some have been blinded by extremists on both sides," Mr Mills adds. For Mr Brian Irwin, managing director of Irwin's Bakery, the family-run business has also thrived on the enthusiasm of its employees in the area.

Mr Irwin's grandfather started the bakery in 1912 in the centre of Portadown and although it is now based outside the main town the family maintains strong ties with the town centre.

The bakery produces a range of traditional breads such as the sodas and the plain batch loaves that it is famed for.

But it has moved with the times to cater for a new generation of tastes and is in the middle of a multimillion pound investment programme to develop specialty breads.

The company supplies to many of Britain's leading retailers, including Tesco. It also owns a shopping mall in the centre of the town, which is now home to a number of well-known high-street names.

Mr Irwin is one of a number of business people who are backing calls for new investment in Portadown town centre to help reposition the town to compete for trade and business.

According to Ms Diane Huniford, the town executive for Portadown, there can be no doubt that businesses in the town have been affected by the images of six years of unrest at Drumcree.

But Ms Huniford says new investors have not been deterred from locating in the town despite the events of previous years.

"We are a thriving town for most of the year but business is affected during the month of July and that is a fact of life that we live and work with.

"Each year we prepare for the worst and we hope for the best. Local retailers have worked hard to build their businesses and they are always going to be here and we have recently seen companies such as Tesco announce major new investment in the town, so people realise that Portadown has good potential," she says.

Civil and business leaders in Portadown have just celebrated the opening of the first phase of the £2.5-million Millennium Court development.

The new arts and shopping complex has been developed in the heart of Portadown on the site of the town's old market.

Ms Huniford believes it symbolises the start of a new chapter in the town's history.

"We are not pretending that there is not a lot more work to be done but there is confidence in Portadown and we have confidence in the future," she says.