THE UNLOST RIVERS OF LONDON Folly Brook Mill Hill → Totteridge → North Finchley (2¼ miles)
[Folly Brook → Dollis Brook → Brent → Thames]
The amazing thing about the Folly Brook is that, although it flows across north London for over two miles, its valley is almost entirely un-built-up. Wealthy Totteridge residents stepped in to protect the land from development between the wars, since when the Green Belt has done the job for them. What remains is mostly farmland, woodland and haymeadows, so that's lovely, although it's not always possible to walk alongside the river, especially in its upper course.
The Folly Brook divides Totteridge from Mill Hill, its valley a gentle dip between the ridges to north and south. It rises near the foot of Holcombe Hill, best accessed by 251 bus if you're coming by public transport, across a field occupied by two grazing ponies. The opening few metres run between clipped hedges through a pristine plank-lined trench, which I suspect forms part of a water jump when horsey types come to ride. Beyond that the fledgling brook disappears off into a wedge of woodland, which you can't follow because the paddock's owners have put up 'Private' signs on every available approach. You sense they don't approve of the perpendicular public footpath, but can do nothing to stop it.
The stream's first mile is accessible in only two places, the first on a footpath sweeping down from Totteridge to Mill Hill. I walked in from the former, the posh linear village preferred by celebs, showbiz names and football managers, which always looks like it belongs in Surrey but was in fact once part of Hertfordshire. On my shady descent I passed a haybaler weaving back and forth to bring in the harvest, and a farmer dashing out to watch proceedings on his red quad bike. Folly Brook was barely visible from the footbridge, recent downpours not having been enough to set this end of the stream in motion.
The ascent to Mill Hill is more eventful, passing through the livestock-filled grounds of Belmont Farm. Take care crossing the horse track, for fear of being knocked down by a canterer, then watch out for grazing cattle and pigs snuffling right up against the path. This large-scale visitor attraction is open to all, especially families with young children, with daily activities including Meet The Cows, Meet The Sheep and Meet The Tortoise. Posters out front also seem insistent that Belmont Farm's cafe serves the finest waffles in London, which must be annoying for any foodies who've been grazing in Shoreditch or Peckham instead.
Mill Hill Village, like Totteridge, is a corner of the capital that makes you gasp "seriously, this is London?" The ridgetop road is lined with posh schools and institutions, including the copper-topped bastion of the former Francis Crick Institute. The High Street is 100 metres of quaint terminating at a duckpond, by the almshouses, opposite a church now taken over by a white-robed congregation with Nigerian roots. A couple of streets of posh houses lead steeply down the hill, one of which screams Private but actually has a public footpath at the end, which subsequently crosses the local cricket pitch on a brazen diagonal.
If you were hoping to read about the Folly Brook, the good news is we're finally back on track. To rejoin it turn right at Folly Farm, a residential fortress with a supremely whiny hound, and the only building along the first two miles of the river. Alongside is a meandering channel, which actually has some water in it after the downpours of the last week, though is nothing special to look at. This section of the walk is a favourite for people who've parked up at the garden centre and fancy a short stroll, nothing too strenuous, maybe down to the gate and back, or perhaps across the next open field. One of Totteridge's ginormous deluxe mansions is wilfully visible at the top of the rise.
A previous mansion-on-the-ridge, Copped Hall, is responsible for the highpoint of today's journey. Its formal gardens included an ornamental lake created by damming the Folly Brook, which was then transformed in the 1970s into Darland Lake Nature Reserve. The lake's also really shallow, which is how I got to watch a heron striding purposefully across the centre in search of lunch. A limited number of footpaths lead through the woodland site, including either side of the lake, with connections to the dogwalking meadows below Totteridge as appropriate. I walked round twice, because all was so joyously peaceful, and also slipped off piste into the trees, jumping across the rippling stream like a big child.
The finest stretch of actual river follows, meandering between earthen banks twisted with roots from towering horse chestnuts. Any other river in London would have been confined in some way by now, this far into its descent, but the Folly Brook has been left to flow naturally because there are absolutely no houses anywhere nearby to threaten. Planks and logs in the footpath hint at the mudbath this track becomes in winter, the underlying clay being easily sodden, and even in August there are sections that'll leave your best trainers anything but pristine.
After crossing the ancient trackway of Burtonhole Lane, the brookside path opens out into Dells Down Acre. Brambly scrub and tracts of open meadow make for pleasant walking, occasionally diverting round the remains of a gate or stile installed when the route was a little less welcoming. Only now do the back fences of suburbia brush down towards the stream, specifically the outer edges of Woodside Park Garden Suburb, one side pre-war and the other-post. Emerging alongside the local Sports Club the river abruptly reaches Southover, the only road it crosses along its entire length.
Ahead, just ahead, is the confluence at which the Folly Brook feeds into the Dollis Brook. What's unusual this juncture is that's totally accessible, simply by stepping off the tarmac of the Riverside Walk and advancing carefully through the trees. The stream ends gingerly, braiding around flat pebbled beds in rippling rills. With water levels low it's possible to step across the shallows to a decaying bench sometimes used by littering lager drinkers, or to stand on the very stones where one brook gently enters the other.
» Pre-1965 the entire Folly Brook marked the boundary between London and Hertfordshire.
» To the best of my knowledge the Folly Brook has not yet featured in the PeterGrant novels, which if you're familiar with Ben Aaronovitch's magical detective series is perhaps surprising.
» There are some excellent walks in this part of Barnet, championed by the Mill Hill Society [map]
» If you'd prefer a longer walk in the area, try the Totteridge Circular, #228 from the Saturday Walkers Club [map]