Ah, the pub, that British cultural icon. There are more than 45,000 of them and I’ve biked to many of the most notable ones.

Among the oldest are Ye Olde Trip to Jerusalem in Nottingham and the Bingley Arms near Leeds.

The latter is best for authentic period features, such as having no cycle parking.

The smallest pubs, on the other hand, might be the Nutshell in Bury St Edmunds or the Signal Box in Cleethorpes. Buying everyone in the pub a drink won’t come cheaper.

The biggest pubs include Brewdog’s The Sidings in Waterloo and Wetherspoon’s Moon Under Water in Manchester; by the time you get from bar to table, you’ve finished your pint.

And I’ve cycled to various olde-worlde, parlour and time-warp-pubs – the Sun Inn in Leintwardine; Tucker’s Grave in Somerset; Birch Hall Inn at Beck Hole in Yorkshire, and more.

However, the top pub of all – in altitude, if not more – is the legendary Tan Hill Inn.

It’s at 1,732 feet, or 528m, on a lonely North Yorkshire moortop above Swaledale: a thrilling ride up from Keld, and a fabulous freewheel down to Reeth.

It served thirsty miners in the 1700s, but the coal and the workers’ cottages are all gone now.

The pub’s now an isolated wonder more than 10 miles from the nearest proper shop, and has featured in books, TV ads and myriad blogs.

But the lowest pub? That’s open to debate. I’ve ridden the drained, sunken fens south of Peterborough, nearly 3m below the zero-line in Newlyn that’s the Ordnance Survey’s ‘sea-level’ reference point.

But OS maps suggest no pub in those fens has a negative altitude. So we’re looking for something by the sea. There are plenty of shoreline pubs and beach bars round Britain’s coast – but which would count as ‘the bottom one’?

I decided on Marsden Grotto, just north of Sunderland. The beachside pub – next to the waves, amid seabird-thronged rock stacks and cliffs – occupies former smugglers’ caves and is only accessible by a special lift down from the clifftop.

It’s said that a bootlegger of old was grudge-murdered here by fellow ne’er-do-wells: something of a moral low too.

It also suggested an irresistible ride. Tan Hill Inn to Marsden Grotto: top pub to bottom pub.

Eighty-ish miles, almost all following Sustrans’s Walney to Wear route (NCN70). Mountaintop to seaside, from historical honeypot to post-industrial challenge.

Barnard Castle, Bishop Auckland, Durham, Sunderland… A pint at either end. And downhill all the way. Sort of. I rode it one chilly day last February. Here’s how it went.

East of Eden

It’s the evening before. I cycle up from Kirkby Stephen train station to Tan Hill Inn. En route, I go past a direction sign that shows distances in furlongs.

I guess the Inn is about 45 furlongs (9km/5.5miles) from here. And about two furlongs up.

The road snakes up the gaunt moors. Below me is the lush Vale of Eden. Above me is a thickening sky and greasy, smeared twilight.

I’m relieved when the Inn’s buttery glow appears in the blue-black distance. There’s no mistaking it: it’s the only building for miles.

I check in to the bunkhouse. I have it to myself, hooray. The pub though is busy with B&Bers, campervanners, adventurous visitors and various musicians performing by arrangement or by accident.

The Tan Hill Inn provides astonishingly complete facilities for somewhere so remote (sometimes New Year parties get snowed in and have to wait days until things clear).

The bar staff might have to stay overnight there too, I suspect.

The live music tonight includes a folk singer: “As I was a-walking through the meadow I spied a maiden fair”, that sort of thing. It’s not my cup of tea – I’m more of a Radio 3 listener.

Anyway, he’s good, and after two pints and a gourmet plate of Whitby scampi and chips, I’m fair myself.

Aurora snorealis

I sleep deep. It’s perfectly quiet and pitch black outside. If you’re lucky, the dark skies show off the Northern Lights to their best up here.

No luck for me this evening, though. My bike overnights in an empty function room. I suspect casual theft here by passing opportunists with bolt-cutters is rare.

Barnard Castle in focus

The following morning, I set off. The small road bounces its way through the mist eastwards over grey-green hummocks and hills to a turn-off onto a gravel road.

A Land Rover driven by a chap in a flat cap overtakes me, casually manoeuvring way off the track to pass wide.

It’s a nice change from country-lane encounters with drivers who refuse to move off the tarmac because a muddy SUV just wouldn’t do in a Waitrose car park.

I crunch through an austere post-mining streamscape, back to tarmac at last, down towards Bowes. Then it’s a busy road to Barnard Castle, notorious for its role in optometry.

Dominic Cummings drove here to ‘test his eyesight’ in 2020, a deed curiously not marked by a blue plaque or signed portrait at the town’s Specsavers.

This morning, the stark castle walls and handsome centre look rather fine, with pavement cafes lively in the fresh sunshine.

I chat to four Dutch cycle-tourists taking selfies. They came here for the hills and the whisky.

Perhaps they think this is Scotland; it can feel a bit like that. They say they’ve had enough hills for today.

Just outside Barnard Castle, and confusingly not in Bowes, I cycle past Bowes Museum. Its palatial facade and gardens have the air of Versailles.

I haven’t time to see its prize exhibit, the Silver Swan, but evidently it’s not working at the moment anyway. Whatever it does.

So I continue east on quietish lanes past unremarkable villages, and along the odd low-grade bridleway, to Bishop Auckland.

The centre is a dismal parade of shuttered-up shops, nail bars, charity stores, budget chains and newsagents. But the bakery is friendly and chatty, and I harvest some lunch.

From the stern Newton Cap Viaduct looming over the Wear, I follow a railtrail bound for Durham.

It’s always a delight and a surprise when you come across a railtrail that’s scenic, smooth and well-provisioned with cafes and picnic tables. Unfortunately, this is not one of those times.

Putting the ‘Dur’ in Durham

Durham is rather splendid on this bright lunchtime, a town of cute independent shops, cobbly lanes and a majestic cathedral – a sort of hillier cousin of York.

I stroll around the lanes resisting the temptation of coffee and cake, and have a picnic lunch in the cathedral area.

I head east out of the centre past some fine historic-looking cottages and play the Sustrans Guessing Game for a couple of dozen miles: should I follow their suggested route down a muddy track then round a chemical plant followed by three sides of a square through a housing estate?

Or go along that B road plied by satnav-following HGVs?

With a success rate no better than random, I find myself at the pleasant Hetton Lyons Country Park.

I enjoy a snack and a spin round a lake, a lovely patch of natural greenery amid otherwise humdrum urban sprawl.

An old man walking his dog asks about my bike, but really he wants to talk. He used to cycle a lot round here, out with his pals every weekend.

After some tower blocks, I’m at another surprise of a pleasant lake, this time on the edge of Sunderland.

It boasts ‘the North East’s Premier Ski Slope’. But it’s grey and drizzly and I’m not hankering after an après-ski Aperol spritz. I’m more in mind of a post-ride, sea-level beer.

I cross the Wear in Sunderland centre and follow the bike path up the coast.

The evening sun comes out and suddenly everything looks embracing instead of just bracing: that monument marking the end of the C2C with Roker lighthouse through its porthole; the gaudy colours of Seaburn’s seaside resort, with its dash of elegance; the slightly surreal appearance of a windmill in the middle of a modern housing estate.

And, at last, the sight of the lift down to Marsden Grotto, a rather industrial and squat building adjoining a clifftop car park.

There’s a hint of 1960s Butlins about it. But yes, you can take your bikes down in it, if you’re a pub customer. Which I very much intend to be.

Low life

I get myself a pint (a tad pricy, but it’s a special place) and sit at a beachside patio table. Any lower than this and I’d get wet feet.

It’s high tide and the foamy breakers are within touching distance, crackling on the shingle. I ceremonially dip my bike’s front tyre in the North Sea.

A million seabirds squabble for airspace round a towering nearby rock stack. Local families laugh and joke over their premium lagers and orange juices. Some Chinese students take selfies.

Somewhere out there, beyond the pale fuzzy horizon, is Denmark.

I cycle back through the evening gloom to Sunderland station for my train home, pondering what makes a pub a pub, not a bar or a bistro or a cafe.

Something to do with territory perhaps, with occupational rights. In a bar, that’s where you drink. In a bistro or cafe, you get served at your table.

You don’t own the area, you’re a visitor in theirs.

But in a pub, you take a drink to your table, and the space is yours for however long. You can chat, read a book, scroll your phone or whatever.

It’s your little circle on the Venn diagram of personal domain, intersecting with others’ as much or as little as you like. Hence ‘public house’.

Ah, the pub, that British cultural icon. I’ve had many highs and lows in them while cycling. But never as literally as this. Cheers!