A £1.5milion restoration project to carry out essential maintenance within the Netherton Tunnel has begun in earnest in a bid to safeguard its future.

The work, being carried out by The Canal and River Trust, will take four months to complete and will stabilise the 155 year-old tunnel walls, after cracks began appearing in the Victorian brickwork.

Opened in August 1858, the unlit 1.7 mile Netherton Tunnel was built entirely by man power, using just picks and shovels – with the risky and dangerous work killing nine men and seriously injuring 18.

The tunnel provided a key link between the main Birmingham Canals and was built wide enough to allow two barges to pass each other and help relieve the bottleneck of other canals nearby – which regularly saw waiting times of over eight hours.

But due to its design and the ground conditions nearby, thought to be affected by mining, the walls were beginning to break off, with fears the tunnel could potentially collapse if immediate work was not carried out.

Using 21st century methods, equipment and health and safety rules, engineers are repairing a 50 metre centre section of the tunnel, by drilling holes into the wall, inserting steel tubes and then filling them with concrete.

Once set, the entire section of the tunnel will then be reinforced with a new archway.

George Ballinger, head of engineering at the Canal and River Trust, said: “We have been keeping a close eye on Netherton Tunnel for some time and have carried out various repairs over the years, the last being in the early 1980s. The centre section of tunnel that will be repaired over the weeks ahead has really got us concerned and, ultimately, if we did nothing the tunnel could collapse.

“The works being carried out will help prevent any further movement of the centre section, giving it strength and support for generations to come.”