The UK’s deepest, longest and highest canal tunnel might also be its most haunted, according to the charity overseeing the site.

The Canal & River Trust (CRT) is marking 25 years since Standedge Tunnel reopened with a Halloween event promising to "scare even the most intrepid ghost hunter".

A crowdfunding appeal has also launched for a purpose-built trip boat for the tunnel, which stretches three-and-a-half miles along the Huddersfield Narrow Canal between Marsden in West Yorkshire and Diggle in Greater Manchester.

Finished in 1811 after 17 years of manual digging, it is recognised as one of the seven wonders of Britain’s waterways.

According to CRT, staff and visitors have reported strange lights, unexplained sounds and rumours of a mysterious robed figure.

Paranormal investigation groups have also explored inside the passage.

The initiatives mark a quarter-century since "the impossible restoration" brought the structure back into use.

Tourists can go on a special Halloween boat trips on the…