The eastern portal, as is the western
one, is a Grade II listed building. The entry at the English Heritage website
[visit
link] tells us:
"Tunnel entrance or portal. 1819-20 by James Morgan,
engineer to the Regent's Canal Company. Brown and yellow brick set in English
bond with stone dressings. Round-arched opening with banded rustication giving
the effect of voussoirs flanked by a pair of Doric pilasters; brick panel to the
parapet; flanking walls with simple piers at either end."
The Canal Museum website [visit link]
includes some interesting photos and tells us:
"All London's canal tunnels are on the Regent's Canal.
Are there two, or three canal tunnels? Only two are generally recognised today,
Islington Tunnel (960 yards, or 886 metres) and Maida Hill Tunnel (272 yards or
251 metres). In fact a third very short tunnel exists, Eyre's tunnel, (53 yards
or 48 metres) under Lisson Grove. Today this is usually incorrectly assumed to
be a bridge. Maida Hill and Eyre's tunnels were opened in 1816 and are near to
the junction with the Grand Junction Canal's Paddington Arm which is now known
as Little Venice. Islington Tunnel was opened in 1820 along with the completion
of the canal, a procession of boats passing through with a band playing, to be
met by a salute of cannon fire as they emerged at the eastern
end.
Islington Tunnel is the major engineering work of the
Regent's Canal. The engineer who built it was the Regent's Canal's engineer,
James Morgan. The early print illustrated to the left shows the west portal,
probably in the very early days of the tunnel before the introduction of a steam
tug. It also interestingly illustrates the type of open horse drawn boat in use
at that time, confirmed by other contemporary illustrations. The photograph to
the right shows the same portal in 1998, at sunset. It is just possible to see
the light at the other end!
The Company initially launched a competition for the
design of the tunnel. The advertisement was placed in August, 1812, but
elucidated little response. A committee of three eminent engineers, Nicholson,
Walker, and Jessop, were to be judges. They received only wild ideas and the
prize of 100 guineas was awarded to a copy of a Jessop design, which was
evidently not considered suitable. The competition having been something of a
fiasco, James Morgan was ordered to get on with it and so he did. There were
delays in starting work as a result of the usual difficulty - landowners! Work
must have started in 1814 for in January 1815 four of the six shafts had been
constructed and 140 yards of tunnel built.
By March 250 yards had been built and all four shafts
were linked at tunnel level. Tunnels were built by the process of sinking shafts
at intervals to the required depth, and then lowering men and equipment down to
dig, and, it was hoped, meet. Accurate survey work was essential in order to
locate the shafts in the correct place and dig them to the correct depth. That
the tunnel is more or less straight indicates that this was done well, although
difficulties meant that headings, small pilot bores, had to be constructed
between shafts initially to ensure it. Things did not progress quite so well
later in the project however, and Morgan found the earth through which he was
digging to be a lot less stable than had been anticipated. A vein of stone
caused ingress of water.
Mindful as he doubtless was of the collapse of a road
tunnel at Highgate in north London, Morgan used substantial temporary support
structures and used stronger brickwork and in places additional brick lining to
add strength. Springs were encountered in the digging of the shafts which made
extra work necessary. The tunnel cost nearly £40,000 to build, a great deal more
than had been anticipated. This was hardly unusual, and indeed even today major
civil engineering projects frequently end up costing much more than expected!
The tunnel was completed at the end of 1818 although not opened for business
straight away.
The tunnel was at first operated by "legging", whereby
men lying on their backs on planks aboard the boat walked the vessel through
against the side walls. This was slow, hard, and caused a great deal of delay.
In 1826 a steam chain tug was introduced, one of the earliest uses of steam
power on the canals. The chain was secured at each end of the tunnel and the tug
pulled itself and a train of barges by winding the chain around a barrel on
board. This means of haulage survived over 100 years until the 1930s when boats
with engines became commonplace.
During the winter period at the start of 2000, Islington
Tunnel was closed for extensive repairs (pictured, left). In June 1818 Thomas
Telford inspected the tunnel and is quoted as describing it as "Perfect, the
materials and workmanship excellent, and its direction perfectly straight". It
has lasted 183 years, so far!"