The very best driving roads in Wales

"First, some ground rules.

I will lead, because this is a lap of Wales, and I'd like to see it, rather than stare at the rump of a Skoda Octavia for 850 miles. However, you shall carry the map, because I have nowhere for it. Yet I insist on doing the directions. I promise not to rely on my internal compass, but to use a portable satnav."

Justin and I are standing under the Severn Bridge, the old one, the proper one. We're armed with my favourite road atlas. It's 300 pages thick and the rough size and weight of a paving slab. It's tattered to shreds and bears the invaluable graffiti of a hundred road trips. We're discussing how this is going to work. It's... complicated. Navigation, clearly, will be an issue. Also communication. Not forgetting the weather, speed bumps, semi-slick tyres, inevitable deafness and oil.

Oil? Yep, I've just dipped the stick, and it's on the lowest mark. We need to find some Motul 300V. Nothing else will do. But I'm excited: I love it here - here being the start of the journey as well as this place. A slipway into the Severn, right at the gateway to Wales. Justin, attempting, I'm sure, to curb my enthusiasm made me reverse down the perilously slippery cobbles. The Mono has no handbrake.

There are many other amenities that it lacks, but given the temper that the Severn seems to be in, swirling angrily, vortices popping in and out of existence, that one is preying on my mind right now.

Pictures: Justin Leighton

We're lost. We take the wrong B-road coming out of Chepstow, the 4293 instead of the 4235. I don't realise until the nav whisks us off down a road of such plunging darkness and narrowness that I fear we're going to be funnelled underground. As if you don't feel small enough already driving the Mono. The right road, when we do reach it, is a wonderful introduction to Wales, a swooping empty B that picks up views of fields and bubbles of trees, all looking freshly laundered under scudding skies. Usk-B4598-Abergavenny brings us to the foothills of the Brecon Beacons, which rise, lumpy and bald, ahead of us. We see-saw back and forth, north and south, heading gradually west, ricocheting from mining village to market town.

I'd never really noticed the starkness of this variation before. The stabs of the mining villages are a living memorial to the area's industrial past. Somewhat dilapidated, these southern ribbon settlements are as blasted as the hillsides above and contrast starkly with the rural pastoralism of the northern flanks. Here, sweeping green views and vistas lead down to comfortably huddled agricultural towns. Drive between Blaenavon and Crickhowell, or Merthyr Tydfil and Brecon, or Brynamman and Llangadog, all of which we do, and you'd swear you're criss-crossing the border between worlds that stand on either side of the Industrial Revolution.

The roads that link these disparate communities across the Beacons, the B4560, A470, A4059, A4067 and A4069, make me wonder why there hasn't been more cross-pollination. These are wonderful, rapid, open roads, good for progress, and in the case of the ones at either end, the roads that head north from Beaufort and Brynamman, spectacularly good to drive. These are high passes, riding the tops of the moors, weaving and darting around, and the Mono loves them both, zapping about, its remarkable ride absorbing the coarseness, widescreen views entirely unimpeded by pillars or roof. Central driving positions are the way forward.

We locate oil at Touratech, an outward bound motorcycle outfitter in Ystradgynlais. Justin, who's partial to an aluminium pannier, is beside himself and walks out happily clutching a catalogue several hundred pages thick.

We have a deadline to meet. So instead of investigating the Gower Peninsula, we hitch our train to the A48/A40 that picks up the baton after the M4 has run its course. I suspect there are good, empty B-roads in these parts, but if we're not at Pendine by 3.30pm, we can't get on the beach. The dual carriageway is quick, but the Mono protests by refusing to hold a steady speed, hiccuping the throttle every few seconds. Accelerate and lift, and it's fine. Odd, but also essential, because that's the only way to stop the mirrors vibrating like hummingbird wings, blurring the rearward view. Plus there's the downdraft. At speed, the wind deflected south by the roll hoop is strong enough to close your nostrils for you. To combat this, I adopt a two-hat-and-ski-goggles strategy.

We swing south from St Clears down the high-hedgerowed A4066 to Pendine. It's a village dominated by caravan parks these days, but 90 years ago its seven-mile beach was the centre of land speed record-breaking. We drive the Mono onto the beach and look along the almost endless expanse of flat sand. There's something about this place. We wander into the museum, a quiet building that looks out over the beach. It's little more than a mausoleum for John Parry-Thomas's car, Babs, so we read about this man who died in pursuit of the 174.883mph record. It makes our little jaunt seem rather tame.

B4314 to Narberth, A40 to Haverfordwest and A487 onwards, aiming to get as far west as possible. We only stop as I thought the sign deserved a pic: Pembrokeshire Motor Museum. At 6pm, it's closed, and the owner of this ramshackle collection of farm sheds tells us the student who has the only key is in the pub. A big barrel of a farmer, he lets us have a nose around his lower paddock. Which is amazing. The brambles have reclaimed most exhibits, but nosing out of the undergrowth is a veritable back catalogue of British motoring: Wolseley, Morris, Cortina, TR7, Transit, Mini. They're never going to move again, but here they are, gently rotting in a very British way.

We weave down to the coast at Nolton Haven, then skirt north on a thin ribbon of fresh but slapdash tarmac called, imaginatively, Welsh Road. In places, where it drops from the tussocky green cliffs to the beaches below, it's already being reclaimed by the pebbles. Picking up the A487 again, past Solva and a mercy dash for fuel outside St David's (the Mono has a 30-litre tank and if I'm being friendly, we're talking 140 miles per fill up. I've had to pre-plot super unleaded stations on the atlas), as the sky's colours get good we're near Wales's most westerly point, parked up at Whitesands Bay.

The surf's up, the sun's out and there's a slipway into the sea. For the second time today, but at opposite points of a country, Justin insists I reverse down a slope. This time, it's really rather magical: a crowd gathers, and we all watch the sleepily warm sun drop slowly over the horizon.

It's now dark, and we're nowhere near our hotel. I have one of those drives in the Mono. There's every chance that the A487, B4331 to Puncheston, B4329 and B4332 are a dull disappointment in daylight, but at night they whip and dive around at the outer reaches of the main beam. It's addictive, not massively fast or at high revs, but the car reacts as fast as the human brain, so we're synched together nicely. The brakes are fabulous, the six-speed sequential race gearbox unbelievably tolerant and good to use. We hole up for the night in Newcastle Emlyn, and when I get there I just sit in the car for a few minutes, ears ringing with deafness, eyes pulling into tunnel vision, brain struggling to adapt to the stillness.

We'd kept an eye on the weather forecast. We knew. When we set foot outside, there's already a puddle in the Mono's seat, and it's getting deeper. I make a note to remind BAC that it needs a drainhole and curse myself for not bringing a tarp. Otherwise I'm prepared. I spent all day yesterday in Musto foul-weather sailing gear, so this is nothing new. I set off in the rain along the A475 to Lampeter, striking north from there (after another fuel stop) up the A485 to Tregaron and beyond.

These are lightly populated A-roads with wide verges, so visibility isn't a problem; nor, you won't be surprised to learn, is overtaking. They're interesting roads to drive, not natural greats with stunning scenery, but roads that make you think and concentrate, force you to do all that IAM stuff about reading the road, spotting the telegraph poles, the tractor mud, all these little clues that formulate into an absorbing detective story.

And then, as we approach the turn off from the B4343 into the Elan Valley, I feel it. The first droplet. It beads behind my ear, deep under two hats. How it got there is a mystery, but I feel it develop, then start to run, trickling down inside my collar. Ten minutes later, I'm damp to chest level, and we're climbing up into more cloud and rain. Visibility is dropping, and suddenly there are sheep wobbling and bobbing up the road in front of me. I can't see them very clearly, as my goggles are fogged up (I'm mainly navigating by listening to the Mono's undertray scuff and clatter along a road as crested as a dutch barn). They form a fluffy agricultural escort for several hundred yards before swinging off. We carry on. There's nowhere to turn round, anyway.

Three miles of laborious scuff/splash later, the road runs out. An error largely caused by my not recharging the Garmin last night. I'm now using pictures of the road atlas on my phone. I execute a 58-point turn and make a decision to head for the coast. The weather's always better at the coast.

The B4340 takes us away from the high reservoirs and back to civilisation. My gloves are now drying on the Octavia's dash, making the Skoda so moistly warm that Justin is driving with the window down. I envy him. But as I de-layer in Aberystwyth in front of the inevitable crowd, a miracle occurs. Clear skies. We huddle over hot coffee and make plans as yet another man comes up to us. I brace myself for the first question as it's always - always - the same: "What is it?" An American accent.

"BAC Mono," I reply, "It's a British-bui..."

"Whoa," he interrupts me, "don't tell me. Bad Ass Car, right?"

The Tour of Britain started in Machynlleth this morning, which means there are road closures on one of my favourite bits of road - the B4518 north of Llanidloes. Go there. The road up the side of Llyn Clywedog is stunning. Instead, we turn left at Machynlleth on the A493 to Tywyn. Pleasing estuary views aside, it's unremarkable, so we strike north-east on the B4405. Ooh, it's good, sweeping lightly up the base of a huge valley until it picks up the A487, at which point it gets... even better. Trouble is, this is west Wales's main arterial road and it's busy. And at this time of year - post-tourism, pre-winter - there are two main issues that impede our progress the length and breadth of this land: road building and hedge trimming.

All irritations vanish once at Bala on the A494. Now, in reply to the endless questions people posed about the car, I always asked one back: where would you go to drive it? Time and again, I got the same answers: the A4069 across Black Mountain to the west of the Beacons; the mountain road from Rhayader to Aberystwyth; and the one, OK two, I'm nosing down now, the A4212 and B4391 to Ffestiniog. I love these roads so much I considered redacting them from the record. The Mono is so stable, so planted on a bucking bronco of a road, yet with the reactions of an acidic housefly. The wetness of this morning is forgotten in a screaming hoon of revs and a gasp of landscape.

As a result, we have to stop before Porthmadog to employ the emergency jerrycan, and from there we make slow progress via toll bridges, further fuel stops and food, to the far coast of the Lleyn Peninsula. Lovely beaches, undulating roads, but little to hold us. I clobber a pheasant. It's shredded by the front suspension and by the time the remains are blown out the back, it's processed and ready for KFC... or should that be KFP? We head on.

Linking Morfa Nefyn-Llanaelhaearn-Penygroes brings us to the B4418 and Snowdonia. We wanted to get to Snowdon itself for sunset, but it's not going to happen. The sun flares one last time and then pops out of sight, leaving only orange shadow lines that rise rapidly up the sheep-spotted mountainsides.

The road past Rhyd Ddu to Beddgelert and beyond is lined by stone walls as solid and threatening as the scenery; shadows and shapes leap out from the uneven stones, clawing at the Mono. It's a combative, intense experience, so we pause in the shadow of Snowdon to eat leftover bread and cheese. In 30 minutes, we see precisely two cars. Cameras are put away, and driving needs to occur. Our hotel tonight is near Denbigh, and that's still 40 miles away.

It's 10.30pm when we get there, and all I want to do is turn round and blast back along the A543, A5 and A4086 again. And maybe again. After all, the Shell garage in Betws-y-Coed is open 24 hours.

On no account are we going to so much as touch England until we're back at the Severn Bridge, so to avoid potential foul ups, after a quick foray over the Clwydian Range above Denbigh (open at the tops, fiddly approaches, all narrow), we head back to Bala. This was inevitable. In this part of Wales, all roads lead there. The B4501 takes us most of the way, and it's a humdinger, peeling across empty moorland, windswept and interesting. Same applies to the easy-to-get-carried-away-on B4391, which packs farmland, forest, moors and the massive valley above Llangynog into a dozen scintillating miles.

Wales settles down into comfier scenery after that, and our pace is tempered by weather and dawdlers. We take the sensible A483 at Welshpool, and for our trouble are rewarded by a 15-minute traffic jam getting through Newtown. Too many chuffing trucks. The Mono copes with it better than I do.

We're going to run the border: the B4355 shadows it all the way to Knighton - Offa's Dyke off to one side, GlyndŴr's Way the other. Very Welsh. It looks good on the map, but as we climb from Dolfor and my hopes rise as trees and fields thin to moorland, they're suddenly dashed. I have no throttle pedal. It has literally vanished. Coasting along, my foot finds it, slack and unsprung, at the end of the footwell. Ah. Ten minutes later, having spoken to some men at BAC who apologised for the three solid days it had just spent on a track, I'm headfirst down the footwell, diagnosing a snapped throttle cable and the impossibility of onwards progress. I'm gutted. And, for a slightly panicky few minutes, stuck fast in a carbon tomb.

It's hours later. The BAC has had to be carted away on a truck, but we still have wheels. It ain't over. B4355 and B4357 take us through Evenjobb to Radnor. Rally country. But even that fails to raise our spirits, the hedgerow-lined farm 'n' field roads hereabouts are tight with little visibility.

Still border-hugging, we cut off the B4594 to Hay-on-Wye, then track south along the tiny Gospel Pass, past Lord Hereford's Knob and other local, er, landmarks. The scenery picks up here, but the road is narrow and after a few elevated miles falls back into the trees. The 11 miles to Abergavenny take an age, and we're pining for our little car. God knows what it must have been like for other drivers as this little firework came grinding and gnawing up behind them, but its absence is hurting. Dual carriageways minimise the pain: A40 and A449 lead quickly to M4 and home.

It's a fizzle of a finish, but we expected nothing else - the good roads and the good scenery aren't to be found around Newport. To get your driving kicks in Wales, you've got to go further afield. Get a road atlas, mind the sheep and aim for the bits beyond the trees.

Yellow: Bridge to Beacons
Green: Into Pembrokeshire
Blue: Elan Valley and beyond
Red: Snowdonia
Orange: The east