(ICYMI: Having executed a 120km circumnavigation of the capital for charity, the writer has produced these blogs to publicise the fundraising and consider the vernacular. There’s a full list of chapter/sections at the end of each blog.)

You rejoin me on the third quarter of a 30km walk which completes a 120km clockwise circumnavigation of the capital, and it’s frankly uphill. But considering this section of the walk careers from Horsenden Hill to Sudbury Hill to Harrow-on-the-Hill, you didn’t need to be a top-class toponymist to expect a little legwork.

Truth be told, Sudbury Hill didn’t require much effort but I’m now devotedly upwarding along a woodland path – officially Green Lane, colloquially Piggy Lane – besides the playing fields of the independent John Lyon School. Upon these fields presumably romped alumni like posh actor Julian Rhind-Tutt, controversial journalist Johann Hari and tobacco entrepreneur Alfred Dunhill, who once invented a windshielded pipe so you could smoke in an open-topped car.

The school itself is further up the mountain in Harrow, which peaks at 124m. And the path suddenly pops out of its sylvan glade into Harrovian splendour, all elegant architecture and electric gates. A bit more ascending and you’re properly into Harrow-on-the-Hill.  

At this point I must admit to a journalistic failing. At most times on this journey, dipping in and out of the suburbs fringing London, I have been able to make sufficient notes as I motored metronomically along, succinctly minuting without sacrificing momentum. But Harrow is a sudden banquet of the built environment: to stuff my pockets with observations here could comfortably take most of the day, and I have to be cracking on for two main reasons of time and tiredness.

For one, at a given point in a long walk the legs no longer appreciate a break if it isn’t a final one, preferably accompanied by a soak in a bath; for another, I am determined to make it to the finish line in time to watch England’s World Cup quarter-final at 3pm.

There’s too much here to talk and write about, and the effect upon a tired mind on a hot day can be overwhelming, like walking into the intricacies of Portmeiron after a lone day in the immense Snowdonian grandeur. I may have to return to write a separate blog about it, or just to peep at lower pace, but what I would say if you get there before me is: Look around. There is much to see. As is the case everywhere, the variety of building types are there to be experienced and enjoyed, if only you look up.

So, snapping wildly with phonecam, I plough onwards through this literally elevated seat of learning. Geologically it’s Bagshot Sands capping London Clay. Toponymically it means “Heathen temple”, obviously – as is so often the case – built upon by the later lot. Topographically it offers commanding views of a capital baking in the July sunshine: I catch glimpses of the City and the Wembley arch between buildings of the eponymous school which dominates Harrow in building and spirit. Founded in the 16th Century, Harrow School has educated seven Prime Ministers, five kings (global) and, perhaps most impressively to many,  Benedict Cumberbatch.

Suddenly, it’s time to take a hard right and come down off the high ridge. As with Horsenden Hill, this happens rapidly, with a half-jog half-fall down a long straight road called, progressively and fittingly, Football Lane and Music Hill.

As Harrow-on-the-Hill is the top left-hand corner of the Capital Trail, it’s now eastward ho for the last 9k of the 120k trail. After nipping across the school fields and alongside a burn, I rather surprise myself by reaching the day’s third and final checkpoint before 12.45pm, a half-hour in front of schedule. With 7.5k to go, so as long as I don’t get injured or ludicrously slow, by (St.) George I’m going to make it…

Immediately after the checkpoint, the trail goes through the trickiest section of its 120km length: a rough narrow overgrown strip between a golf course and the Northwick Park Hospital which was the setting for Green Wing and Sybil’s ingrowing toenail in the Fawlty Towers episode ‘The Germans’. I’m glad it’s a dry day because this could be very tough going in the rain.

As it is, I plunge happily on, the path proper reasserting itself in Northwick Park. Utterly devoid of company, I spend my time constructively. The idea has come to me that there is a sociomusicology piece to be written about Three Lions, the 1990s football anthem whose plangently hopeful message (“It’s coming home”) has asserted a grip on a sentimental nation as a genuinely likeable England team peacefully progresses through the World Cup.

ANALYSIS Home, heart, failure and longing: why Three Lions is such an important song in English culture

Dictating phone-notes about football and society is a fitting way to spend the time as I walk through the north-western suburbs, pacing through parks and passing sports centres. Just beyond South Kenton is a shapely 1938 pub called the Windermere, which I later learn is Grade II-listed for its Dutch style “fusing Art Deco and historicist… the building, unusually little altered, demonstrates the efforts breweries went to at this time to create attractive drinking places for an expanding suburban clientele”.

That said, and bearing in mind that my brain might have been burnt out by the Harrovian architectural speedball, I can’t pretend these suburbs are a feast for the eyes. There’s one called Preston which I’d never heard of (well, apart from the one in Lancashire); Preston Park is pleasant, and at Preston Park Primary School – where they “respect the individuality of all pupils” – they’re having a summer fair. It’s now ten past one and there’s a certain worried air about George Cross-clad dads who are only just dragging their various progeny toward the tombola.

To be blunt, Preston is the sort of place where people dump furniture outside their own house. A mercifully short blast of high street includes the Preston Road station of the Metropolitan line; suitably, at 33 and 35 Uxendon Crescent there’s an astonishing pair of 1930s houses.

Sadly, the astonishment is not a positive one. These classic Metroland houses, all rounded render and what look to my untrained eye to be Crittall windows, could be gorgeous – but they’re falling apart, their curtains in rags, their render cracking and collapsing, their paving weed-strewn. Unless they’re on a sinkhole or a septic reservoir I’m amazed they’ve not been bought and improved. There’s been a lot of piecemeal improvements around here: many a drive has been repaved in a style du jour which has now become a style d’hier, and many now have weeds growing up through them. It’s not the grand gesture but the constant care that’s needed, the modern equivalent of soap-stoning your front doorstep.

Musing upon this (I mean, what would Kevin McCloud say?) I duck under the Jubilee Line – excitingly, the next station townwards is Wembley Park – cross the canalised Wealdstone Brook and divert down a ginnel. Although the path runs alongside the tube line, I’m back on green ground and starting what my map implies to be the final parkland section. It begins in what feels like ancient woodland, and I determine to enjoy myself.

Such resolve weakens when I emerge into a hayfield. It’s now July and tinderbox-dry - above my childhood home, the West Pennine Moors have been aflame for a week – and most of London’s grass is yellow, so they might as well bale out...but it’s still a surprise to find this quintessentially bucolic scene hard by a Tube track. They haven’t yet filled every field with homes.

The surprise is superseded by sweat. Walking across, and up, a vast open hillside field maybe a quarter-mile across is a daunting undertaking as I start to attack the last major uplift, Barn Hill. By now I’m alternating between two states of attempted heat-aversion: wearing hat and shades, followed by removing both to douse my head with carefully-aimed squirts of the water topped up at the last checkpoint. As I grunt onwards a family plays on a bale, idyllic and happy.

After a gruelling five minutes I’m in shade – albeit still ascending – as trees enclose Barn Hill. Here, the Capital Ring climbs to the very peak of the hill, where there’s a pond - quite shrunken in this heatwave, to the distress of the heron who stands motionless in its reeds. Pointlessly but pleasingly, the Ring runs right the way round the pond before disappearing off downhill a short hop from where it climbed. Again, I take the half-fall half-jog option, hat and glasses bouncing around like Eric Morecambe avoiding a mugger.

Back at the bottom of the hill it’s a woodland walk to the A4140 which noisily bisects the Fryent Country Park. It’s a new, temptingly fast road but an ancient route: parallel to the A-road is a possibly prehistoric route from Westminster to Hertfordshire. Known locally as Elderstrete or Hell Lane, it is bounded by a hedge dating back to Saxon times but is probably older – indeed, “Street” in its Anglo-Saxon sense usually means paved highway, which generally means Roman interference, although those lads tended to use the nearby Watling Street. Elderstrete was used by pilgrims travelling to the shrine of St Alban, the first English martyr; in Saxon times it would have been used by the Elders or aldermen. As I cross the A4140 and nip through the car park back into the green, there’s a bloke asleep in his Vauxhall.

The Ring has one more hill for me to climb as it ascends to the highest point on the eastern half of Fryent Park. From the hilltop – the most northerly point of this quarter – there’s an expansive and pleasant view to the north and west, towards Watford and St Albans, but unlike those ancient pilgrims my attention is focused southwards.

The signpost atop the hill points back the way I came, saying 17m back to Richmond Bridge – that was this morning. Pointing south in the general direction of Wembley stadium, it says 26m to the Woolwich Foot Tunnel – that’s from weeks ago. Most excitingly, it says it’s 1.5m to the Brent reservoir. It’s 1.50pm and I set off down the hill.

As the last mile beckons, I leave the greenway behind for one final dreary suburb. I have thoroughly enjoyed the Capital Ring’s split personality of urban and rural stretches, and enjoyed the gradations of the borderlands between – the edgelands, as they’ve been called by the poets Michael Symmons Roberts and Paul Farley in the evocative book of that name. But eschewing an orthodox notion of hierarchy doesn’t automatically bestow an equal enjoyment of all environments. There are stretches of the Capital Ring to which I will return; there are others I will be perfectly content never to see again.

But by now my legs are propelled by anticipation of closure (not to mention food, drink, seating and a big football game). And even the dullest or ugliest suburb can contain a pretty place, or one with an interesting back-story. St Andrew’s, Kingsbury, has both.

One of London’s prettiest Victorian churches, this Gothic pile was opened in 1847… in Wells Street, just east of Oxford Circus in central London. When that area turned from domestic to warehousing and commercial eight decades later, the parish dwindled and the church closed, but the idea of demolition prompted an outcry. With the booming suburban population needing more churches, St Andrew’s was taken apart stone by stone and reassembled in Metroland, a three-year jigsaw puzzle completed in 1934.

Reconnecting for the last kilometre with the path that I took from the tube station all those weeks and miles ago – and passing the Grade-I original St Andrew’s church, superseded by the import, closed in 1977 and recently loaned to the Romanian Orthodox congregation – I see a family out enjoying the sun and I’m fairly sure it’s the boy I saw on that first morning, fetching home the Saturday loaf. Now he’s out helping his younger brother wheel a trike down the hill, broadening his horizons.

And that’s all I’ve done. On this walk I’ve seen some of the best that London can offer, and some bits you can keep. The daughter who closed out the third quarter wants to do the full circuit next year; I may come along for some of it – I may even rewalk some sections before then – but I may also leave her to discover it with friends, or maybe even among her own thoughts. I’m glad that I have spent around half the walk alone, and half with strangers who became friends. And as I walk up the final road behind the Wembley Sailing Club, where I know a television has been set up to watch a football game which will be won by the latest representatives of the country I love, a cheery voice calls out to me across the street. A Mencap volunteer, who I would assume also receives some of the many benefits provided by this wonderful charity, says hello and we walk across the finishing line together. He tries to refuse his medal, saying he’s only walked round the corner, but we insist. Sometimes we all walk alone, but if we like, we can all walk together.

NORTHERN QUARTER, SAT 5 MAY 2018
• Pt1: Wembley to East Finchley • Pt2: …to Finsbury Park
• Pt3: …to Clissold Park • Pt4: …to Springfield Park
• Pt5: …to Hackney Wick • Pt6: …to Bow Back River
• Pt7: …to Channelsea River • Pt8: …to Royal Victoria Dock

EASTERN QUARTER, SAT 26 MAY 2018
• Pt9: Victoria Dock to North Woolwich Pier • Pt10: …to Maryon Park
• Pt11: …to Hornfair Park • Pt12: …to Oxleas Wood
• Pt13: …to Eltham Palace • Pt14: …to Grove Park
• Pt15: …to Beckenham Place Park • Pt16: …to Penge
• Pt17: …to Crystal Palace Park • Pt18: …to Upper Norwood

SOUTHERN QUARTER, SAT 9 JUN 2018
• Pt19: Crystal Palace to Beulah Hill • Pt20: …to Streatham Common
• Pt21: …to Tooting Bec • Pt22: …to Wandsworth Common
• Pt23: …to Wimbledon Park • Pt24: …to Richmond Bridge

WESTERN QUARTER, SAT 7 JUL 2018
• Pt25: Richmond Bridge to Isleworth • Pt26: …to Hanwell Locks
• Pt27: …to Horsenden Hill • Pt28: …to Sudbury Hill
• Pt29: …to Wembley, and that's that