The Victorian viaduct is lit by a pink and orange sunset. The sky deepens to cloud-studded red and violet during the 10-minute walk to my B&B along Berwick-upon-Tweed’s old town walls. On countless train journeys between London and Edinburgh, I’ve looked out of the window near the Scottish border and been drawn to Berwick’s long, arched bridges, its polygonal town hall spire rising over the rooftops, and the river widening to meet the sea. Finally, I am stepping off the train here rather than hurtling past, ready for castles, boat trips and wintry waterside walks, full of wildlife and history. Berwick’s border location meant for centuries it was the scene of Anglo-Scottish skirmishes. Before you leave the railway station, a sign announces that here, in 1292, “the claim of Robert Bruce to the crown of Scotland was declined”. The town and its castle, whose ruins are right next to the platform, changed hands 13 times in the next 200 years. Britain’s only bastioned town walls now form a mile-long amble around the major sights, with medieval ramparts overlooking the Tweed, and Elizabethan fortifications towering above cave-backed beaches. A car-free winter weekend by the sea, with late sunrises and early twilight, has many moments to savour: window-gazing in all weathers, windy clifftop walks, and lingering fireside pints. An incandescent dawn lights my first circuit of the town walls. The air smells of kelp and roasting coffee. The beaches below are empty of people and alive with wading birds: noisy oystercatchers, stilt-legged redshanks and seaweed-brown turnstones. Grebes are diving under the Old Bridge, herons stand guard on grassy cliffs and ogee-shaped threads of geese patrol the skies. The afternoon brings more coastal wildlife, including eider ducks, cormorants and seals, as well as views of the town walls from the water. Berwick Boat Trips now operates cruises on the smart new Border Belle into the winter months and visitors regularly spot dolphins near the estuary (from £9 child/£12 adult). “Pesky dolphins, we call them,” says the skipper, David Thompson. “You never know what they will do, when they will do it, or how fast, but we’re always pleased to see them.” Several streets in Berwick have clusters of independent shops. My favourite is Bridge Street: there’s bike hire, a Green Shop (organic, fair trade, eco-friendly) and the Curfew micropub, where I drink a creamy oatmeal stout from Cheviot Brewery. Atelier, opposite the pub, is a good wine bar and bistro. A generous bowl of Sri Lankan vegetable soup (£5) is full of spice and coconut, and the vegan platter (£9) is heaped with artichoke hearts and aubergines, roast peppers, home-pickled fennel, gingery chutneys and stuffed vine leaves. Next morning, I catch bus X18 to Seahouses (day ticket £6.70). Coastal views from the bus windows include Lindisfarne’s hilltop castle and plovers on the shining mudflats of Budle Bay. There are dozens of curlews in the stubbled fields, and cows roaming the dunes. Just outside Seahouses harbour, gannets are diving headfirst into the sea at speeds of up to 60mph. Fulmars and glossy green shags are sitting on dolerite pillars, while rock pipits scurry over the outcrops. From Seahouses I take a boat trip to see the grey seals of the Farne Islands (child £15, adult £20). Thousands of grey seals live here, and the birth rate of pups in the huge colony grew by 62% between 2014 and 2019. As we cruise past, they are everywhere: curious, whiskered faces surface just metres from the boat, while scarred bull seals rest on the rocks. There’s a drone hovering near the red and white lighthouse: it’s used by rangers to count the thousands of pups. Heading back to the harbour, we pass puffins swimming, and surreally beautiful vistas of the castle-spangled coast. Ten minutes back towards Berwick on the bus, Bamburgh castle (child £6.95/adult £14.10, 20% discount when you show your bus ticket), on its volcanic headland, towers over a wide beach. It’s one of several local attractions offering 20% off for visitors arriving by bus. I climb a sandy path through banks of honey-pungent flowering ivy to the castle gatehouse and explore nine acres of towers and terraces. Christmas decorations are up, there are carols playing in the King’s Hall and sparkling greenery decks fireplaces and stairways. Up the road in the vaulted sandstone crypt of St Aidan’s church (free), rows of zinc boxes house the bones of people who lived in cosmopolitan Anglo-Saxon Bamburgh. Winter storms in 1816 ripped open the nearby sand dunes to reveal a seventh-century graveyard; recent analysis of bones and teeth show that many of the people buried here came from what are now Scotland, Ireland, Scandinavia, Spain and even north Africa. Back on Berwick’s Castlegate, I have haddock goujons and colourful salad (£10.95) at Coull’s, which opened six weeks ago. Owners Bob and Natasha Coull have run the chippy next door for decades. This place was until recently an old-school model shop. Now, there are old photos of Berwick on exposed brickwork, bright, fish-themed wallpaper in the loos and palm trees on the outdoor deck. The Walls B&B (doubles from £90 B&B), in a quayside Georgian townhouse, has a log fire and an honesty bar in the lounge, and fresh milk for coffee. Breakfast options include a great fruit salad, homemade potato cakes or smoked fish from Eyemouth with local stottie loaf. Three big rooms look out over the River Tweed, so you can seal-watch from the upstairs windows, and the pink front door opens on to a pedestrianised stretch of medieval ramparts. The Granary gallery, in the old Maltings next door, has an exhibition of quilts until February (free). Five minutes east along the walls there’s a Russian cannon, complete with double-headed eagle, captured from Sebastopol in 1856, in the Crimean war. Nearby is an 18th-century barracks originally designed by Nicholas Hawksmoor, which houses the town museum (closed until spring, £5). Earlier this year, the museum bought a local beach scene by LS Lowry, who also painted the cobbled alleys and townscapes nearby; one of Berwick’s many trails follows in Lowry’s footsteps. The next day, there are roses still flowering in Alnwick Garden (child free, adult £9.35), a leisurely ride from Berwick on bus X15, past views of the misty Cheviots and sheep grazing on ridged medieval farmland. I wasn’t sure how much any garden could be worth a trip in late November, but Alnwick’s formal fountains and neatly clipped hedges are as much about shape as colour. Brainchild of Jane Percy, Duchess of Northumberland, the garden opened 20 years ago and now features a bamboo maze, the world’s biggest Taihaku cherry orchard, with 50 swing seats, and a macabre collection of toxic plants. Scarlet rose hips and butterball crab apples shine like natural Christmas baubles in the ornamental garden; tiny wrens and robins are hopping under dense, pink Joie de Vivre roses, wine-dark Burgundy Ice, and subtly scented Maria Theresas. I take refuge from the serpentine beech walks in the fairy-lit Treehouse restaurant with a pot of North Shields mussels. Revived, I walk on down the road, across the Aln, and through the fields to the Lion Bridge, with views across the river to the gothic magnificence of Alnwick Castle. My last morning’s hike is a couple of miles along the Tweed, under the viaduct, for coffee and a homemade fruit scone in England’s most northerly garden centre. Crossing the river to head back through coppery beech woods, I spy a boat made of driftwood near the castle ruins. In the afternoon, I take a trip to Scotland before my train leaves. Bus 235 heads 20 minutes up the coast to Eyemouth, where fishers are busy in the harbour. The nature reserve at St Abb’s Head is a four-mile walk along the coast path, but the sun is already setting, turning the sandstone cliffs still redder. Herring gulls cry plaintively over the crash of the breakers and the water glows like rose quartz in the gloaming. Train travel was provided by LNER (advance tickets from London to Berwick-upon-Tweed start from £33.80 one way, booking recommended). Accommodation was provided by The Walls B&B. For further information see Visit Northumberland and Northumberland AONB This article was amended on 8 December 2021. It was the throne of Scotland that was claimed by Robert Bruce, not the throne of England, as an earlier version said.