This one can be found at the Yorkshire Sculpture Park, about 50m south of the main visitor centre. The artist responsible is Brian Fell, but YSP haven't been able to tell me who the bridge designer was.
I like the assymmetry, the way it's like a giant stencil split in half, an idea crying out to be used somewhere else on a more "serious" bridge.
I'm not 100% convinced by the rust colour - it doesn't look in photos quite like weathering steel and even if it was, the detailing would lead to significant corrosion over time in the various sharp corners. It would also have been nice if the side panels actually held up the bridge - from the photos it looks like the deck is strong enough to be self-supporting.
For non-UK readers, a "ha-ha" is essentially a posh ditch. Well, there's more to it than that, but that's the basis of the bridge-as-pun that has been sculpted here.
[Photos from Flickr used with permission]