The UK does not lack high-standard walking and hiking trails, with the National Trail association in England and Wales, the Walk Northern Ireland organisation and Scotland's Great Trails combining to cover the majority of scenic attractions. People cannot, however, pitch a tent just anywhere along them without permission. Hikers planning to "wild' camp should be more than half a day's walk from an official site and observe discretion and restraint, keep the campsite small and take away everything they bring in.
The Ulster Way
Walk Northern Ireland has a special treat for those wishing to exert themselves over 1000km (625 miles) - it's The Ulster Way that circles the five counties, much of it along the coast. The Ulster Way was launched in 2009 and is a combination of existing walks, for example the Lecale Way (in the steps of Saint Patrick) and the Mourne Way that inspired CS Lewis' Narnia series. The trail divides into "quality" sections, that are genuine walkways, and "link" sections that largely follow public roads. Campers should use discretion and avoid being too close to waterways.
Three lochs, including Loch Lomond
The Three Lochs Walking Route in Scotland, which links Loch Lomond, The Gareloch and Loch Long, starts from Balloch and covers 52km (32 miles). In the summer months ferries on Loch Lomond allow walkers to link with the West Highland Way on Lomond's eastern shore. The trail's establishment has taken sometimes delicate negotiations with landowners, so the appeal is out for respect at all times, and observing the Scottish Outdoor Access Code. This particularly applies to camping because the Balloch holiday park does not allow tents and the route has no other commercial campsites. Walkers must "wild camp" responsibly.
Deep in mid-Wales and bordering Snowdonia, the 217km (135 mile) Glyndwr's Way is part of the National Trail system and offers some of the principality's finest scenery, from country lanes to open mountain country. Walkers can enjoy Glyndwr's Way at any time, even winter when a snow covering makes it spectacular. Campsites and bunkhouses are rare and of the six listed as of May 2012, three are at the Knighton end of the trail. The trail has a number of bed and breakfast hotels to compensate for the lack of campsites.
West Highland Way
Campsites are hard to come by on the West Highland Way -- the 154km (96 miles) which starts from near Glasgow and goes to Fort William in the Highlands, including alongside Loch Lomond. But at Sallochy on the banks of Loch Lomond, the Scottish Forestry Commission offers attractive loch-side sites for £5 per night, as of May 2012. Mobile fire pits are for hire from the warden. Most hikers travel north, using the easier southern sections to get fit for the Highlands. The final section into Fort William has incredible views of 11 mountains over 3000 feet.
The Hadrian's Wall walk is best from east to west, from Wallsend (near Newscastle Upon Tyne) to the Solway Firth, though either direction is fine. It's 135km (84 miles) long and the National Trail website notes the undulating terrain quickly sorts the fit from the unfit. The National Trail walk opened in 2003. While the wall is prominent in parts, it leaves the walker wondering where it went in others. The trail has 10 campsites and five camping barns along the route, as of May 2012, and National Trails advises against wild camping outside those areas.
Causeway Coast Way
From Portstewart in County Londonderry to Ballycastle in County Antrim, Northern Ireland, the 55km (33 mile) coastal walk has many highlights, ranging from the World Heritage site, the Giant's Causeway, to Dunluce Castle. Howevert none are more appreciated than the striking coastal scenery along the way. Parts of the walk follow secondary roads and the WalkNI website warns of high tides that might impede hikers. The website offers little information about campsites, indeed any accommodation.
Offa's Dyke Trail
Historians and keen walkers alike will relish the 285km (177 mile) Offa's Dyke Trail along the Welsh/English border, which celebrates the earthworks of the Mercian King Offa (757 to 796). It runs from coast to coast and most walkers take the south-to-north route. Terrain varies, from the tough undulations of the Shropshire Hills and the Brecon Beacons to the flat section from Buttington Bridge and Llanymynech, alongside the Severn River. The National Trails recommends two weeks over the journey and campsites appear at regular intervals according to the accommodation map for the path.
Cleveland Way, North Yorkshire
The Cleveland Way is a National Trail that runs 176km (109 miles) along the North Yorkshire coast and moors. It opened in 1969 and was one of the first national trails in England and Wales. While pubs and accommodation offer a great Yorkshire welcome along the trail, campsites, ranging from commercial sites to farms, pepper the route. The trail starts inland in Helmsley and crosses the moors to reach the sea at Saltburn-by-the-Sea and travel south to Whitby and Scarborough before finishing at Filey -- travel in either direction is fine.