AS I compile this week’s budget a couple of weeks ahead of publication, two of my teenage grandsons are undertaking a long-distance walk from Carlisle to Wallsend along the Hadrian’s Wall path.

They are accompanied by my son-in-law, who is their father, and for part of the journey will also be joined by my son. They are completing the walk during a week of manageable stages, resting at youth hostels or boarding houses along the route.

They have all been in training for a while, with the boys already having completed a 20-mile walk along the coast from Scarborough to Whitby, and another one from Thirsk to Ryedale, where I live.

Clearly, we are all very proud of them and I know they enjoy these treks, with the Hadrian’s Wall walk being the climax of their summer activities. For them, there will be the excitement of achieving something out of the ordinary.

Even in modern times, there are arguments about the original purpose of the massive wall.

Some accounts suggest it was merely a commercial means of acquiring taxes from people travelling north and south through its several gates, but the more widespread belief is that it was built by the Romans as a defensive fortification.

Work began in AD 122 when Hadrian was Emperor, hence its name, and it was one of two such fortifications across Great Britain.

The other, much shorter, was further north between the east and west coasts of Scotland, roughly from Glasgow to Edinburgh, or the Firth of Clyde and the Firth of Forth in modern terms. It was known as the Antonine Wall.

Hadrian’s Wall stretched from the shore of the Solway Firth and extended via Carlisle to Wallsend, a very apt name because Hadrian’s Wall ends there.

It is some 73 miles long (117.5km) and built of stone and turf found in the locality.

There are points where it rises to a height of 16-20ft (5-6m), with a base about 10ft (3m) wide, interspaced along its route with ditches, berms and forts where the defence forces were billeted.

A berm is a raised bank near a river or canal, or a narrow ledge between a ditch and the base of a parapet.

Upon completion, it was said to be the most heavily fortified border in the Roman Empire, and it is now one of the most popular tourist attractions in the North of England, being selected as a Unesco World Heritage Site in 1987.

Some experts regard it as the most important monument built in Britain by the Romans.

Contrary to popular belief, it did not mark the border between Scotland and England.

Hadrian’s Wall lies entirely within England, although it reaches very close to the Scottish border at Bowness-on-Solway.

It took around six years to complete the building work, the construction being undertaken by several Roman legions, with each legion building a stretch of about five miles (8km).

The differing stonework and construction materials along the route vary according to the materials obtained locally.

Various types of stone have been utilised and some stretches of the wall were built with turf.

One account suggests that when it was completed, the stones were painted white so that it could be seen from a great distance.

What is amazing is that so much of Hadrian’s Wall has been preserved for almost 1,900 years. Much of that is due to the efforts of a 19th century gentleman called John Clayton, who was a lawyer and town clerk of Newcastle in the 1830s.

After visiting the wall, he became highly concerned about its survival.

Organisations and individuals were helping themselves to the stones that formed the wall, which was causing widespread damage.

To stop this vandalism, Clayton began to buy sections of the wall to deter landowners and farmers from removing the stones. Much of the present wall has survived due to his intervention, a role that has since been taken over by the National Trust.

I know that my grandsons regard their long walk as a marvellous means of gaining first-hand knowledge of our history. That famous wall is living history.