east portal (2K)

Engineering Aspects

The Greywell Tunnel

ENGINEERING

Greywell Tunnel

Ash Aqueduct

Frimley Aqueduct

Water Supplies

The tunnel that nearly wasn't!

When it was first surveyed, no tunnel was planned for the Basingstoke Canal. The route was to have passed around the north side of Greywell Hill.

map: proposed route of canal (7K)
map: actual route of canal (7K)

However, the Rt Hon Earl Tylney put forward objections to the Parliamentary Bill that the proposed line of the canal would cut off some of his lands from Tylney Hall. So the line of the canal was altered to pass through the hill.

A start on the construction of the canal was made in October 1788 at Woodham in Surrey, but at the same time, because of the immense task, a start was made on the tunnel. It was to be 1,230 yards (1125m) long, and was to become one of the longest canal tunnels to be constructed in the south of England, and the 12th longest in Great Britain.

east portal (5K)

A few weeks after work had started, a Rev Shaw visited the site and described how he saw "above 100 men at work preparing a wide passage for the approach to the mouth, but they had not entered the hill". Working with just picks, spades, wheelbarrows and by the light of candles, the conditions must have been terrible.



INSTANT FACTS

Tunnel length:
1230yds (1125m)
(12th longest in UK)

Depth below hill (max):
131ft (40m)

Construction (approx):
1792

Major roof collapse:
1932


The tunnel was dug by the normal method of the 18th century where shafts were sunk at regular intervals along the line of the tunnel and then adits were driven out in each direction from the bottom of each shaft.

construction shafts (4K)
kink in roof (4K)

Where these adits meet it is possible to see the slight errors in navigation which have resulted in 'steps' in the walls and kinks in the line.

The Canal Company's records show that by June 1791, 223 yards (203m) of the tunnel had been completed, a year later 635 yards (580m) and by November 1792 just over 200 yards (189m) remained to be cut.

Records show that the quality of the bricks supplied for the work on the tunnel was a constant source for concern, and in 1789 the brick maker was sacked.... In November 1790 the Company declared that John Pinkerton must ensure that bricks supplied for the tunnel "shall be proper for such work".

interior brickwork (6K)
old photo: western portal of tunnel (8K)

On 4 September 1794 the canal was opened, but within six weeks of the opening the southern bank of the canal near the western portal collapsed, blocking the canal for 100 yards. This was followed by a second slip and the canal was not re-opened until the following summer.

The tunnel was often in the local news. In October 1827 a boy was drowned in the tunnel and in 1878 there was a roof fall. The last commercial traffic through the tunnel was to and from the Nately Brickworks which opened in 1898. The brickworks produced 2 million bricks in 1899 alone, so this last traffic must have been considerable. The yard closed in 1901.

map: Nately Brickworks (7K)
ENGINEERING

Greywell Tunnel

Ash Aqueduct

Frimley Aqueduct

Water Supplies

A J Harmsworth's last trip (K)

The last boat to navigate through the tunnel was probably the Basingstoke owned by Mr A. J. Harmsworth. Having left Ash Vale with 10 tons of sand on 16 November 1913, it finally arrived at Basingstoke Wharf in February 1914. The time taken indicates the poor state of the canal.

In 1932 a serious roof fall finally closed the tunnel and the western 5 miles of the canal were abandoned.


(More on A. J. Harmsworth's last trip)

(based on an article in BC News 66, February 1976)

Last updated April 2000