The canal tunnel on the Huddersfield Narrow Canal was authorised by an Act of Parliament on 4 April 1794. Construction of a -long tunnel began months later. Within two years, cost-saving measures pushed back its completion date and progress was slowed by the high levels of water which were much greater than had been expected. It proved difficult to secure skilled help, some tenders went unanswered and Benjamin Outram withdrew from the venture. In 1807, Thomas Telford drew up a new plan for its completion. In 1811, the tunnel opened. It is the longest and oldest of the four Standedge tunnels and is the longest and highest canal tunnel in the United Kingdom. Having been closed to all traffic in 1943, the canal tunnel was re-opened in May 2001.