This week's route is planned to take me from Marsworth Junction, where a narrow arm of the Grand Union branches off to Aylesbury, some 74 miles via 48 locks and couple of crackingly good tunnels to the fearsome pair of five-rise staircase locks at Foxton, near Market Harborough in Leicestershire.
From Tring, perched on the top of the Chiltern Hills with its quartet of summit-level reservoirs dug between 1802 and 1839 to feed the canal (and now a protected haven for wildlife), the cut now tumbles away from Marsworth into open country, down past Leighton Buzzard, down into the valley of the Great Ouse. But before the canal crosses this relatively great river, flowing north-east for 100 miles or so before emptying into the Wash, it weaves its random way through the gridiron fabric of Milton Keynes.
Once over the river it begins a gentle climb to a new summit level that includes the 2,000-yard Braunston tunnel. Long before that the canal arrives at Stoke Bruerne, once a large stabling, repair and transshipment centre, now one of the key museums of canal life in the country. It is just south of the 3,000-yard Blisworth tunnel, the last link in the canal opening in 1810 five years after rest of the navigation. Shortly after leaving the north portal of the tunnel the Northampton arm locks down from the mainline to join up with the River Nene and the Fenland Middle Level Navigations created by Dutch water engineers in the seventeenth century to drain this most fertile part of the United Kingdom.
Staying on the mainline through Watford Gap, where canal, railway and motorway run side by side, the cut reaches Norton Junction. Here, the mainline, which is broad - that is has locks and bridge mouths at least 14ft wide - virtually all the way to Birmingham, turns westwards while my route takes Leicester arm of the Grand Union, a true narrow cut with locks and bridges unable to take any craft wider than 7ft.
After climbing a flight of half a dozen locks and passing under the M1 and the 1,500 yards of the Crick tunnel, a peaceful meandering 20 lock-free miles open up, broken only by 1,200 yards of the Husbands Bosworth tunnel before the cut arrives at the first really scary feature - the Foxton double staircase locks; two sets of five where each chamber empties into the next. You have to keep a very clear head to navigate these locks, particularly as, at least during the summer months, you are under the gaze of hundreds of sightseers.
Fortunately, there is usually a resident lock-keeper to lend a hand to the operation, a merciful climax to the this week.
· Mike Holland will be writing weekly online dispatches from his canal journey around England. Thanks to the wonders of wireless technology, you can email him at michael.holland4@btinternet.com
