A DAMP squib. Yet worth igniting. But could it backfire? That perhaps sums up the new right-to-roam in the Yorkshire Dales and North York Moors, where the contentious measure came into force late last month.

So far, there has been no report of any phalanx of walkers plunging recklessly across pathless moorland, trampling grouse eggs and scattering birds. Nor is this alarming spectacle, the vision raised by landowners anxious about the right to roam, if not hostile to it, ever likely to appear.

The vast majority of walkers simply want to walk on clear, unobstructed paths. For most of the time, the remaining small minority shares that modest aim. But in pursuit of special interests, say archaeology or natural history, some occasionally wish to leave the beaten track, perhaps to explore an earthwork, visit an historic stone or seek the habitat of a rare bird. With rare exceptions, such walkers are knowledgeable and caring of the landscape, and would not choose to wander off path at sensitive times.

In fact, across virtually all the North York Moors and most of the Dales there has traditionally been an ipso facto right to roam. In half a century of walking these areas, coinciding with their history as national parks, I have never been turned off a moor, though a gamekeeper on Lord Ingleby's Snilesworth estate, near Osmotherley, did once point out that the track I was following was not a right of way. He said I could use it provided I respected the privilege.

This raises two vital points. Though ramblers have largely enjoyed grace-and-favour access to grouse-moor vehicle tracks in the Dales and Moors, only regular walkers are aware of this.

Others, especially visitors on holiday, have been unwilling to venture where the map doesn't show a right of way. This has deterred walkers from using, for instance, certain Land-Rover tracks around Bransdale, even though that area officially became access land years ago in a pioneering tax-relief deal.

Now, however, all walkers can stride out on any moor path with confidence. Since most want to do no more than follow the defined track, and it is hard to envisage an army of walkers suddenly adopting any hitherto little-used route, it seems unlikely that the newly-opened areas will suffer the damage feared by landowners. Soon we will all be wondering what all the fuss was about.

Hence that damp squib analogy.

But the welcome it nevertheless signals to all walkers is one reason why it is worth igniting. And there's another. The goodwill of landowners that has underpinned the ipso facto right to roam could have been withdrawn at any time.

To give just one example. Rights of way on Penhill, that most prominent Wensleydale landmark, do not visit Penhill Beacon. Though a track leads there, and many take it, the landowner could, until last Saturday, have closed it.

Thanks to the legal right to roam, this historic viewpoint is secured. Anywhere on our unenclosed uplands, the nation's most prized recreational lung, the walker is now there by right - a truly great and precious thing.

And yet ... Is it possible that the legal right could lead to less access? A hint of this backfire is contained in an article in the Moors Messenger, journal of the North York Moors National Park, which states: "Local restrictions may well be in place during such times as the sensitive bird nesting season between March 1 and July 31."

Since this is less than a fortnight before the Glorious 12th, which ushers in the three-month grouse-shooting season, another "sensitive" period, ramblers might not infrequently find the newly-open door shut in their face.

For landowners can close their land for up to 28 days, plus other periods for land-management, public security or fire risk. Usually posted in the past only as a fire precaution, closure notices look like becoming a familiar feature in the Moors and Dales. Walkers who have hitherto used non-rights of way without let or hindrance will rightly feel as obliged as any other not to enter areas where restrictions are advertised.

Walkers with dogs must always confine themselves to existing rights of way.

Since dogs, even on leads, effectively neutralise a wide swathe of moor for wildlife, the denial of a right to roam for them is justified. It remains to be seen whether the broader arrangements work out for the better or worse.

Lyke Wake Walk closures apart, my only encounter with "local restrictions" was once on access land on the Duke of Devonshire's Wharfedale estate, where I found two moors closed on the same August day. The hope now must be that landowners apply the restrictions lightly and sparingly.

When it becomes apparent that the right to roam has not triggered the catastrophe they feared, there will be no reason for a heavy hand.