Barely visible in the gloom of the deep underground cavern, illuminated only by the miner’s lamp on my helmet, is a small, shoulder-level opening in the rocks that looks like a drainage hole.
“OK. It’s the end of the tour and that’s the quickest way out. You up for it?” asks Donna, my guide.
The alternative is a long, stooping trudge back to the entrance of this 2,000-year-old Roman gold mine. I grab the handrail, pull my helmet down tight and worm my way back up to daylight – and fresh, sweet, Welsh air – via a near-vertical cascade of slippery, rocky steps.
It’s day two of the Brecon Beacons Great British Drive and the most spectacular demonstration yet of this region’s astonishing – and mysterious – industrial past, at the Dolaucothi Gold Mines.
The 195-mile tour starts at pretty Abergavenny, “gateway to Wales”, in the rather cosier surroundings of the Angel Hotel, where you should work up an appetite for its splendid fare by tramping ruined, adjacent Abergavenny Castle and its meadows sloping down to the gushing River Usk.
Next morning, head towards the Blaenavon World Heritage Site on the B4246 and, as your bonnet points skywards, enjoy views to Sugar Loaf Mountain and beyond.
Look carefully – a little imagination is called for while stopping at lay-bys offering relief on this mountain road – and identify the ghosts of the iron-processing industry that once formed the heart of this community. Here the ruins of a forge, there a slag heap, centuries old, returning slowly to grass, aided by Forgotten Landscapes project volunteers.
Follow signs into Blaenavon and, at the preserved Ironworks (free entry), discover how the workers lived, worked and died, how small children laboured and how the ironmasters paid workers in company tokens redeemable only in company shops.
Stroll to Blaenavon’s picturesque Broad Street – a jewel of a period timepiece, recently rescued from dereliction – and treat yourself at the aromatic Blaenafon Cheddar Company.
Follow the B4248, A467, A465 and at Merthyr Tydfil, for a more scenic route, take the A470 towards Brecon for 9.4 miles before turning left onto the A4059 to Penderyn. Now, celebrate remembering to pack your indispensable TomTom with a dram (a sip if you’re driving) on the £6 tour of Wales’s only malt- whisky producer, named after the village.
Reprogramme your satnav (although, fortunately, losing your way in the Beacons invariably delivers rich rewards in the form of unexpected discoveries) and follow the A465, A4109, A4221, A4067 and A4068 before soaring along the stunning A4069 towards another ruined castle (didn’t they look after anything in Wales?).
The gaunt, grey, broken teeth of sombre Carreg Cennen Castle dominate the landscape for miles and it’s well worth the £4, half-mile slog on foot for spellbinding views from the top where you can, if you wish, “pothole” to another cave hidden deep inside the fortress. But take a torch. In the tea room below, Nia tells me that her grandfather, tenant farmer Gwilym Morris, bought the castle by mistake in the Sixties.
What vendor Lord Cawdor’s solicitors didn’t spot – but clever Morris soon did – was that by buying the land he had farmed for years, ownership of the six-towered castle automatically passed into his hands too.
It’s to the monument of another revolutionary Welshman – Wales’s own “Braveheart”, Llewelyn ap Gruffydd Fychan, executed in Llandovery by Henry IV of England for supporting Welsh rebellion – that a run over the edge of Black Mountain now takes you. Follow signs to Llandeilo then fly along the top of the hills to Bethlehem, then the A4069 to stop in Llandovery’s car park, dominated by a 16ft steel statue to the Welsh martyr, standing guard over the fine Castle Hotel.
What better way to end your day than in the hotel’s friendly restaurant... serenaded by the Llandovery Male Voice Choir, which rehearses in the ballroom. Join them for a pint in the bar afterwards and they’ll tell you how to find the National Trust’s Dolaucothi Gold Mines, along the A482, next morning. But keep a clear head for the pretty, winding road there – and that miner’s lamp scramble...
Afterwards, the tour carries you back into the national park (A482, right on A40, left on A4069, right to Myddfai) as you head for a cup of tea, or lunch, at the buzzing new Myddfai Community Hall, opened by Prince Charles in 2011.
Next, I pushed on towards Llanddeusant before turning left and left again to sit beside peaceful Usk Reservoir, where I enjoyed a picnic, expertly prepared by the Llandovery Castle Hotel’s chef. Sublime.
Continue past the dam, heading for Sennybridge and then the A4215/A470, for either The Regimental Museum of The Royal Welsh or Brecon cathedral.
Head south on the B4558 towards Bwlch, then sharp left on the B4560 past Llangorse Lake, then up into Hay-on-Wye. If it’s festival time, dally to enjoy the cultural events. If it isn’t, browse the bookshops, enjoy a cup of tea and stroll the lanes before the highlight of this tour: some of the best scenery Wales has to offer, as you seek out romantic (and only partly ruined) Llanthony Priory.
Head south, inside the national park, and climb. and climb. I was glad of the traction system, lusty diesel and brilliant automatic gearbox of the Mercedes-Benz CLS 250 as I drove up through the clouds, which later parted, just as I reached the summit of Hay Bluff.
Descend again – careful, it’s tight and windy, and there are sheep – and pause amid the peace of the former Augustinian priory, victim of the Dissolution.
Your final treat awaits as you head south west, following signs to Crickhowell and the splendours of courtly, Victorian Gliffaes hotel.
Choose a room with a balcony, throw open the French windows and, once again, sit high above the Usk, as the sun sets on a wild and beautiful drive.
Nearly 200 miles long, mostly inside the Brecon Beacons National Park. Steep climbs and plunging descents deliver unforgettable views, scenic and urban. The route takes in Wales’s industrial past, along with ruined castles, picturesque towns and remote, rugged mountains.
The best places to stay
Angel Hotel, Abergavenny, ££
Former coaching inn with smart Georgian façade, 35 bedrooms and public
areas given a modern twist. Additional rooms in former stables. (01873 857121; www. angelabergavenny.com; doubles from £111 per night, b+b).
Llandovery Castle Hotel, Llandovery, £
Friendly ‘gastro pub’ with strong, regional flavour. Traditional bar, log fire, and antique furniture in cosy bedrooms. (01550 720343; wwwcastle-hotel- llandovery.co.uk; ‘better room’ doubles from £95 b+b)
Gliffaes Country House Hotel, ££
Get-away-from-it-all, four-star Victorian former family home with artfully-appointed rooms, beautiful gardens and stunning views down to the River Usk and mountains beyond. Stylish and comfortable, with food and wine to match. (01874 730371; www. gliffaeshotel.com; standard doubles, from £109-170 b+b).
The best places to eat
The Walnut Tree, Abergavenny, £££
Offers ‘proper dining and drinking in an informal setting’. An eclectic menu ranges from Wye Valley asparagus with morels and hollandaise (£10) to Dover sole with Jansson’s temptation (£24). (01873 852797; www.thewalnuttreeinn. com; 6.30pm-10pm Tuesday-Saturday, closed Sundays, Mondays).
Carreg Cennen Castle Tea Room £
Where better to admire the castle, than from the tea room below? Dishes include homemade Cottage Pie (£6.25), jacket potatoes (£4.95) and toasted sandwiches (£3.95) and eat them in the big barn. (01558 822291; www. carreggcennencastle.com; open 364 days a year, 9.30am-5.30pm summer, 4.30pm winter.)
What to avoid
• Don’t forget to check out www.visitblaenavon.co.uk and www.breconbeacons.org before visiting
• Sheep roam freely along many of the routes; take great care.
• Pack a compass, sat-nav and map, too avoid getting too lost.
• Don’t be afraid to make your own diversions en-route; numerous routes lead to most Park destinations.
• Don’t say the "Brecons", they don’t like it. You’ll be safer "in the Beacons".