The pub in question is The Cosmopolitan Hotel and it is now part of a Ghost Tour.
The tour’s official website talks about the tunnel beneath the pub:
‘The Tunnel area has now been blocked off with a door as staff are too terrified to venture near it. Its got a wicked reputation since activity started back in the 70’s, at least this is on the record. All starting after alterations and the cellars were renovated. Worked stopped and its half finished as workmen refused to carry on near the tunnels.’
Scary? It was for my brother whose boss spotted the TV interview and wondered what he was doing in the pub in the afternoon instead of working!