Compass points (an occasional feature where I visit London's geographical extremities) NORTHWEST London - Drayton Ford Bridge, Springwell Lane, Mill End
London has no right to continue as far northwest as it does, no right at all... except Middlesex did, and so the deed is done. The former county's western boundary followed the River Colne, as does Greater London's today, all the way up from Heathrow to Rickmansworth. After ten miles of north/south the Colne valley bends off to the east, and it's at this point that the London border breaks away from the river to pass between Moor Park and Northwood. A snout of land sticks up in the intervening space, a mostly-unneccessary corner of Hillingdon where almost nobody lives and which might as well be in Hertfordshire. The fact it's still not gave me the excuse to visit.
I made my assault on the northwestmost point in London by walking up the Grand Union Canal. This intertwines with the River Colne for miles, the towpath an easy track to follow even at the height of midwinter. Heading north from Harefield, the Colne breaks away at a bridge by a sewage works with a particularly pungent aroma, creating an outer London island between the two waterways. Here you'll find the Springwell Reed Bed, the largest reedbed in the capital, where dry grasses rise above head height from squelchy water. There's no immediate access for those on foot, not until the canal reaches Springwell Lock and a path leads off, back round a hidden lake.
The lock is your typical Grand Union construction, with a low arched bridge to carry Springwell Lane across the water. London's Low Emission Zone starts here with a heavy climb Harefield-ward, or there's an access road to the left leading to the Springwell Chalk Pit, which Doctor Who's pretended is an alien planet on many an occasion. Two buildings that look like waterside warehouses are in fact recent blocks of flats, these where London's northwesternmost residents live, somehow further from Charing Cross than inhabitants of central Watford. And here too is the start of the Hillingdon Trail, a 20 mile ramble across the borough to Cranford, perhaps not best tackled in December.
Those in search of extremity must head northwest up Springwell Lane. That's past a yapping hellhound behind locked golden gates, and watching out for haulage company tipper trucks careering down the lane never expecting to meet anyone on foot. Concealed on the left is Springwell Lake, accessed via London's northwesternmost car park, a remote and uneven affair targeted at twitchers and wildlife lovers. Meanwhile across the hedge on the right is another large expanse of water, Inns Lake, the smallest of several hereabouts but still a massive 16 acres in size. A multitude of wintering birds hang out around here, so now's an ideal time to visit, and isn't that a heron standing motionless on the far bank? We'll come back this way, if that's OK.
It's not far along the country lane until London peters out. To one side of the road a screen of trees hides something drably levelled, then the big warehouse behind a security fence is Mill End Pumping Station, the capital's most northwesterly installation. And that's the boundary with Hertfordshire ahead, at Drayton Ford Bridge, a very short span carrying the lane over the River Colne. It's not much of a river here, more a tamed channel, but that was deemed good enough back in the day for the edge of Middlesex to be so aligned. Two objects confirm that we're in the right place, one a Welcome To Hillingdon sign on a pole, the other a white coal tax post tucked into the verge above the stream. There used to be a pair of these boundarymarkers here, but the other is the unlucky soul spirited away to the Guildhall Museum in London an an exemplar exhibit, but currently consigned to the stores.
A few steps further on are the western outskirts of Rickmansworth. Interestingly there's no sign to announce this, as if the county's trying to keep stumm, but I knew immediately because I recognised the design of Three Rivers' lampposts. A couple of cottagey houses kick swiftly in, then the Uxbridge Road, then the outlier estate of Mill End. Plenty of people live here, tucked higher above the flood plain, in Metroland avenues ideal for learner drivers. I passed my driving test barely a mile away, and failed it twice too, never realising that London was quite so close at hand.
Finally, let's retreat to the joys of Greater London's borderline waterworld. These lakes all used to be gravel pits, extracted between the wars, and gravel from here was used in the construction of the original Wembley Stadium. Now they're part of an extensive nature reserve, each with footpaths round the perimeter, and a splendid stomping ground if waterfowl are your thing. The largest is Stocker's Lake, from whose banks I spotted cormorants, moorhens, coots and a black swan, plus something unidentifiably chunky nesting in part-submerged woodland. The county boundary cuts straight across the lake, with the well-known Rickmansworth Aquadrome spread out on the eastern side. But why go there when you can revel in the capital's distant wetlands, beyond the canal, for a birdwatching bonanza?