Far beyond Belfast's tensions lies one of the world's most spectacular coastlines - as Simon Calder discovers on a trip along the edge of Antrim
One hundred degrees? The thermometer may have climbed that high where you were this week, but on the coast of County Antrim the temperature stayed well within two Fahrenheit figures. Were there a scale for scenery, though, this shoreline would surely score higher than anywhere else in the kingdom. Two of the UK's most stunning pieces of coastal scenery are separated by seven miles. And between them lies an absurdly beautiful beach.

Yet this tableau is but the denouement of a story which begins much further south and west along the shore.

World travellers think they can list great coastal drives at the drop of a place name: Highway One in California, the Great Ocean Road in the Australian state of Victoria ... They should add the A2 from Larne to Cushendall. For 25 miles, the road crouches between the land and the shore, leading you past a succession of scenes. First, ungainly suburbia; next, standard- issue, ultra-green Irish farmland; then brutal cliffs, through which the road occasionally drills. (Punctuating this tale of majesty, though, is a series of ragged urban settlements for which the cliches "quaint" and "charming" can remain safely stowed in the thesaurus.)

Not that the residents aren't friendly, mind. You know the sorts of organisations where a house rule insists that the phone is answered within four rings? The Northern Ireland Tourist Board appears to have a similar policy to help tourists. If any visitor enters a pub alone, one of the locals is obliged strike up a conversation within 10 seconds. I tested this on three occasions this week, and it worked every time.

Soak up the stout with a helping of dulse - dried, salted seaweed which some locals believe deserves to be as ubiquitous as potato crisps. When you track some down by following one of the signs beside the A2 advertising "Dulse, 100 yards", you find out why it isn't: the taste resembles spinach- flavoured Sellotape.

Cushendall represents the end of the easy ride along the coast; no highway could be cut in the cliffs north of here. Prettier and more concise than other towns on the coast, Cushendall is the best base for exploring the Nine Glens of Antrim that carve up the nearby countryside. Each valley has been chiselled out of the ancient rock by a river; some are fearsomely steep, but the A2 follows the path of least resistance along broad Glencorp. At Cushendun, you could continue gently along the inland route. Be tempted, though, by the signposted "Scenic route via Torr Head", which lives up to its promise.

In a series of switchbacks, the road claws along the coast, reaching 650ft at Green Hill (a fellow cyclist I met had amended his map to replace the understated word "Hill" with something much more graphic). Apart from the odd wheezing cyclist, you feel quite cut off from the rest of the world. The only visible company is the dark, brooding shape of the Mull of Kintyre, 13 miles away across the North Channel. You start humming the tune, and by the following day are still doing so (and cursing Sir Paul McCartney for his anthem to the Scottish peninsula).

Ballycastle, where normal life resumes, is a bit of a boom town this summer. The old ferry link to Campbeltown, abandoned around the time Paul McCartney had a Christmas No 1 with his dirge, has been reinstated. Never mind that the vessel that the Argyll & Antrim Steam Packet Co is using, MV Claymore, has enjoyed many better days; the route opens up all sorts of possibilities for travellers wanting to make a circuit of Scotland and Northern Ireland.

The town remains endearingly unaffected by the attention; the garden of the house three doors along from my hostel featured an old bidet in place of a plant pot.

Most of the new arrivals turn right out of the harbour, and start climbing the cliffs to the west. Five miles out, at the apex of a hairpin bend, a sign points towards Carrick-a-Rede, which translates from the Gaelic as "road in the rock". Follow the signs to see why: the rock juts out into the sea like a bulky semi-colon, separated from the shore by a narrow channel (the "road") hewn through sheer cliffs.

The average visitor comes here for a cheap thrill. The channel is crossed by a terrifying rope walkway, agitated by even a benevolent breeze. Two at a time, tourists teeter across the 20 yard divide. Those with unkind travelling companions are instructed to pause halfway across to pose for the camera. Dogs, a sign helpfully warns, are banned - any hound would certainly tumble through the worryingly open spaces between the ropes and the plank, along which a petrified Japanese girl is stumbling. Seabirds circle and heckle, while waves emphasise the rocks 200 feet below by repeatedly smashing against them.

The great thing about Carrick-a-Rede is that you are drawn here for the crack, but stumble across a splendid vista of seascape. The island degenerates into the sea after a couple of hundred yards along the footpath, but from it you can survey its stout sibling, Sheep Island, and gasp at the scale of the shoreline (or is that in trepidation at the prospect of the return journey?).

Assuming you make it, continue along to another National Trust treasure: White Park Bay. Were you to design the perfect beach from scratch, it would look a lot like this: a mile-long arc of blanched sand, sheltering between two mighty headlands. What makes White Park Bay special is what's absent: no buildings beyond a couple of handsome houses, and no people - presumably because this is Antrim, not Antigua.

No other island can boast Antrim's final phenomenon: the Giant's Causeway. As bees will testify, nature adores a hexagon. For geological and geometric proof, take the trail down from the coast road to a sight for which, like all real wonders, no photograph can prepare you. An ancient volcanic eruption somehow crystallised into a chorus of hexagonal columns, each a subtly different height. They tesselate together to form a broad promenade into the sea. You find yourself drawn to the coda, shiny with spray, and turn to face the exquisite detail of the causeway against a magnificently barren backdrop. At dusk, you find yourself alone, yet again.

To go from this to surveying number plates might sound eccentric. But I wanted to find out whence the few visitors that there were had come. So for the hour's cycle ride home, I counted. German tourists were tops, followed by French and Dutch. Not one vehicle, though, from England, Wales or Scotland.

One reason for three-quarters of the United Kingdom perversely avoiding a spectacular coast was summed up on the road sign announcing, truthfully: "Antrim's Coast - an Area of Outstanding Natural Beauty". Someone had spray-painted the initials of the Ulster Volunteer Force over the sign, and an accomplice had plastered "Victory at Drumcree" in large blue capitals across the width of the road. But not once this week did the coastline feel like a front line.

Simon Calder paid pounds 27 to sail from Cairnryan to Larne aboard P&O's Jetliner (01224 572615). He returned from Ballycastle to Campbeltown on the Argyll & Antrim Steam Packet, the Claymore, fare pounds 23 (0345 523523). He stayed at Kathleen Quinn's bed and breakfast at Shramore in Cushendall (012667 71610) for pounds 15 a night, and paid pounds 6 a night for a bed at the Castle Hostel by the harbour in Ballycastle (012657 62337). More information: Northern Ireland Tourist Board, St Anne's Court, 59 North Street, Belfast BT1 1NB (01232 231221). No map is necessary for the stretch between Larne and Cushendall (just stick to the A2), but beyond that, sheet five of the Ordnance Survey of Northern Ireland 1:50,000 series is recommended.