What's up with Queensbury Tunnel?

Abandonment: the current direction of travel for Queensbury Tunnel, costing the public about £3 million. Repair: the aspired outcome of a campaign group who want the structure to form part of a future cycle network connecting Bradford and Keighley to Halifax.
What will the outcome be? Crucial to the tunnel's ultimate fate is its condition. Can it be repaired at a sustainable cost, bearing in mind that the 30-year economic boost from that cycle network has been estimated at £37.6 million, of which the tunnel contributes around £10 million from increased tourism?
In this video, we take a tour through Queensbury Tunnel from south to north, looking at the defects - good, bad and routine. There's much to do if the tunnel is to have a useful future, but the money earmarked for abandonment - destined for a black hole - would substantially fund its repair and conversion.
Photographic Archive: Four by Three/Forgotten Relics
Aerial Image: Google Earth/Infoterra Ltd/Bluesky
Music: Better Days - bensound.com