Built by the Romans to keep back the Scots. Hadrian's Wall has become a mecca for walkers. From this week, as Owen Unsworth reports, they will be able to tread its full 84 miles.

The Roman emperor Hadrian would probably be horrified by the number of invaders his magnificent wall now attracts. The extensive remains draw people from around the world and you are just as likely to bump into an Aussie or an American as the Scots and Picts the wall was built to repel.

Until now, visitors have been unable to walk the full length of the wall, but that is set to change with the construction of a new footpath. Known as the Hadrian's Wall Path National Trail, it is part of a £6m investment by the Countryside Agency (CA) aimed at boosting tourism and the local economy while protecting the Roman remains for future generations.

The new route, which will be officially opened on Friday, is an unbroken and fully signposted 84-mile coast-to-coast walk running from Wallsend in the east to Bowness-on-Solway in the west. This will be the first time that some sections of the wall have had any sort of public access since the end of the Roman occupation, affording a superb opportunity for visitors to take in ruins and views of the surrounding countryside not seen for centuries.

More than half the finance has come from the Heritage Lottery Fund. The money has been used to create new rights of way, improve the condition of existing routes and install new stiles, gates and bridges. Much of the work has been carried out by local council staff, some of them recruited as part of the project.

An archaeologist has overseen construction work and the CA has sponsored archaeological digs and research projects in the area to ensure the works do not disturb any undiscovered ruins.

David McGlade, the CA Trail Development Officer for Hadrian's Wall Path says: "We've deliberately set our standards high. For example, all of our footbridges are made out of steel and oak, which is two or three times more expensive than a traditional bridge. It's the same steel as the Angel of the North and has a design life of 125 years.

"The trail isn't just going to be here for five minutes, the benefits have to be long-term and we want people to know we have taken great care in how we manage it. From our point of view, access that comprises the integrity of the wall is just not acceptable."

Classified as a World Heritage Site, Hadrian's Wall is one of Britain's most important archaeological monuments. Built in AD122-130, the wall originally stood 6m tall and 3m wide and, despite centuries of weather damage and re-use of stones by local people, the wall is still an impressive feature.

To preserve the look of the wall special surfacing techniques have been applied to strengthen the ground while allowing grass to grow through. David McGlade says: "Where the ground is green we aim to maintain it in that state, so the hard path surfacing has been kept to a minimum. Most of the engineered work is in the central part of the wall, in the North Pennines National Park, where we've had to repair historic damage."

All the surfacing works have now been completed but some stretches may remain in a delicate condition until the resown grass is fully established. In particular, visitors have been asked to avoid the section between Chesters and Heddon-on-the-Wall until the footpath is officially opened.

Strange as it may seem, it is hoped that the creation of the new path will help to protect the wall from erosion caused by the huge number of visitors. Problems with overcrowding and erosion were first formally identified in 1976 when the Countryside Commission (now the CA) investigated the management of the wall. The resulting strategy for Hadrian's Wall was published in 1984 and proposed establishing a long-distance footpath, with the aim of helping to spread visitors out over the length of the wall, easing pressure on the most popular sections.

Almost 20 years later the plan has finally come to fruition, marking a triumph over sceptics who claimed the complex exercise was doomed to failure. Some archaeologists believed the footpath would threaten unexcavated sections of wall, while landowners were fearful of tourists causing havoc on their land. But skillful diplomacy and a huge injection of cash from the CA has won through, silencing the critics with well-designed visitor management measures and generous compensation packages for landowners.

Thanks to more than 30 miles of new rights of way, walkers can now avoid the hazardous B6318 which runs parallel to most of the wall. But it is not just walkers who will do well from the scheme; it will also bring significant economic benefits to the surrounding area. The CA estimates that around 10,000 people will walk the route end-to-end each year, generating in the region of £7m per year, a figure which equates to about 80 jobs along the wall corridor. Furthermore, it is believed that the number of end-to-end users will increase to 20,000 by 2006.

The complete walk is expected to attract more serious hikers although, in truth, it is not especially challenging in nature and any reasonably fit individual could complete it in a week. The highest point is only 1,300ft above sea level and much of the trail is on grassy surfaces, but you may encounter some fairly wild weather thanks to the exposed position of the wall as it runs along the top of ridges and crags. For those without a week to spare there are more than 40 newly-created circular walks starting from key points on the wall, aimed at day walkers and tourists.

But investment hasn't just gone into footpath improvements, visitors' centres have also been updated and interpretation boards situated at points of interest. New maps, a glossy guide book, and even a "trail-passport", which can be stamped at various points along the route, are now available in what amounts to a relaunch of an international treasure.

English Heritage (EH) believes the wall has been undersold for too long and has plans to invest a further £7m in its management. Dr Simon Thurley, EH chief executive, said recently: "We need to look at it as more than just a monument. It is as important as Stonehenge, but it has never been thought of in that way. It isn't just a wall, but a complex of forts, temples, turrets, museums and reconstructions that bring the frontier to life."

For many people in the North the value of the wall has never been in doubt, be it as internationally important archaeology or just an interesting day out with the family. It is certain, in these times of overcrowding and urban living, that people will continue wanting to experience the bleak beauty of Hadrian's Wall country. If we are to protect this great structure without making it a museum piece, then the new measures are all too necessary. The irony is, of course, that this wall built to protect civilisation now attracts those wishing to escape it. The hordes that descend on the fortifications these days are not barbarians, but tourists.

* Further information, including a walking and accommodation guide, travel details and a leaflet on walking the wall, can be obtained from the Hadrian's Wall Information Line: (01434) 322002.