Bull's Bridge to Watford
The constant smell of coffee permeates the air from the start of the Paddington Arm at Bull's Bridge, and soon you understand why, when the word Nestle is revealed amongst the steaming factory towers directly in front of you. After a modern development, there’s a line of factories and then you pass, without really noticing, ‘the stunning architecture and fantastic location of one of Europe’s most successful business parks’ i.e. Stockley Park.

Bridge 191 brings more new properties together with their very own Tesco complete with moorings and you aren’t too far away from Cowley Peachey, where the GU jabs a straight left in the form of the Slough Arm next to the Packet Boat Marina.
The last commercial traffic to Slough was in 1960 and it was subsequently very nearly filled in, re-opening in 1975. It is now home to a successful annual canal festival.

The houseboats that stretch past bridge 189 lead to long term and visitor moorings at Cowley South, Cowley Lock, and the Toll House café. You get the feeling that suburbia has been well left behind as you cross the road next to the Malt Shovel pub, Uxbridge however lurks to the right of the canal when you reach The General Elliott (built in 1824) next to Dolphin Bridge. Uxbridge isn’t a bad town, at least it has some history - the first stage on the coach journey from London to Oxford and, well before that, where Charles I had held crisis talks in The Crown with his parliamentary foe during the Civil War.

From Dolphin Bridge you pass Browns Meadow and a nondescript business estate, visitor moorings and Denham Marina (formerly Way's Wharf). There’s now noticeably less rubbish strewn because the residents use the canal as an amenity rather than a dumping opportunity. The A40 is the next main road to go under and onto Denham Deep Lock and Fran’s Tea Garden. Adjacent are nature reserves and trails as you traverse wetlands resulting from gravel extraction with only pylons pockmarking the landscape.

The canal straightens up and it is here, just before the current railway bridge, that the HS2 will zoom over the canal and River Colne on its way to destroy the Chilterns. Passing a marina you continue to Widewater Lock and onto Black Jack’s Lock. More swish properties are followed by the giant Maple Lodge sewage works. After Springwell Lock there’s long term moorings with sets of tables and chairs before you leave the London Borough of Hillingdon and start to enjoy the Hertfordshire countryside - the land of chalk streams, old gravel pits converted to nature reserves, watercress beds and paper making - where the canal has a symbiotic relationship with the three rivers Chess, Colne and Gade.

After Stocker’s Lock there’s another Tesco at Batchworth built on the site of Walker’s boatyard. There’s also Salter’s Cut aka the Gasworks Arm off to the left that once served Samuel Salter’s brewery. Bridge 172 allows you to continue along the canal away from the visitor centre, going by a café before passing a line of boats and onto Lot Mead. The Metropolitan Line crosses the canal on its way to Croxley before you reach Common Moor Lock. From here the canal goes under various road and rail bridges including one huge structure near Bridgewater Boats taking the Met to Watford. You walk past a large variety of boats including impressive wide beams and permanent structures built on the water. Soon there’s Cassiobridge Lock and then, adjacent to the rugby and football pitches, is Iron Bridge Lock and then the Cassiobury Park Locks.

The towpath however is full of bikes, people, more bikes and more people. The reason for all this traffic is Cassiobury Park, the largest expanse of green in Watford. You leave the park behind and get a little peace at bridge 166, crossing to the other side of the canal. There’s a sharp bend at bridge 165 and then again at 164, then a striking white decorative bridge, leading to The Grove golf course, one of the country’s finest apparently. The bridge looks good at any rate.

Cross bridge 163 to the other side near Lady Capel’s Wharf where once boats were gauged for the payment of coal tax and you arrive at her eponymous lock before going under a busy M25 feeder road. Not far is Hunton Bridge Locks and it all gets a bit loud as the canal nestles between the A41 and the West Coast main line. But it's not unattractive and The Dog & Partridge is within easy reach of bridge 162 if you need a break.

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p1 lock
Hover over bold italic text and photographs for extra information.
Grand Union Canal Horse Escape Steps
Grand Union Canal Bulls Bridge
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Grand Union Canal Grove Bridge
The main commercial wharf serving Watford
The canal was originally planned to take a different route with locks from Ricky, through a tunnel west of Hunton Bridge and then an aqueduct at King's Langley onto Boxmoor. However it was re-routed following the Gade Valley and the ornamental bridge is part of the deal with the landowner Lord Clarendon
One of the last places to receive coal from the canal
Black Jack was a negro supposedly hired by a local landowner to harrass boatmen. The next lock, Copper Mill, refers to the Mines Royal Copper Company who had their works here in 1803, the venture failed in 1839 and eventually the site was used for asbestos manufacture in 1882
Just before this pub on the other side is the Uxbridge Boat Centre occupying the site of the old Fellows, Morton and Clayton boatyard (1896-1949)
The deepest on the canal, dropping 11ft
The 45th lock south from Cow Roast in just under 25 miles and the start of the long level into London
Formerly the HQ of the British Waterways' Grand Union carrying fleet, the name perhaps originates from a bull that ran wild in a nearby field and was killed on a bridge over the River Crane that became known as bull's bridge
Slough Arm leaving the GU at Bull's Bridge
Batchworth Lock 82 from under A404 London Road
Grove Bridge, Watford, restored 1987
Two birds looking for lunch at the Denham Country Park
Paddington Arm leaving the GU at Bull's Bridge
Horse escape steps at Hanwell Locks
Croxley is of course a famous make of paper and John Dickinson chose Common Moor to build a paper mill in 1829. it ceased production in 1980. A ubiquitous business park is now on the mill site and Common Moor is a SSI.
More recent political history was created by Christine Keeler who was a local girl made bad but, possibly of more importance, RAF Uxbridge was the location from where the air defence of south east England was coordinated during the Battle of Britain.
The surrounding areas were well known for gravel extraction and brick making. London’s demand for locally produced bricks was the reason the Slough Arm was constructed in the 1880s and in return London sent Slough its rubbish.