Tunnels in the North West

[Storm 911]

I've lived in Manchester most of my life, and I just can't think of any decent sized tunnels in the surrounding area that might prove useful for 'testing' a new exhaust.

Have I just not noticed any, or is there really nothing like that nearby?

[Storm 911]

Thanks for the advice. Looks like Manchester Airport is my best option. It's certainly the closest.