What is the longest UK Cave in the Jurassic Limestone

[Moors Miner]

We would welcome some suggestions to the answer to this question. 

 

[Ed W]

Longest one down south would almost certainly be the Blacknor / Sandy Hole system on Portland.  The old separate surveys prior to the connection showed 600m+ for Blacknor Hole and c.400m for Sandy Hole.  The connection did not add a great deal of passage, but the subsequent extension from the end of Ammonite Passage in Sandy Hole (1995) certainly did.  The survey is yet to be published, but my recollection is that the Ammonite extensions are probably in excess of 2km (it seems a LOT more as there is nothing bigger than hands and knees, and most of it lower).  I would therefore make an educated guess that the system is 3km+ in total length.  Hope that's useful...

 

[Moors Miner]

Thanks Ed
The reason i ask is that we have been speculating about a possible connection we hope to make in the not too distant future on the  north york moors.

 

[Les W]

I will point out that the cave Ed is talking about is a Jurassic Limestone cave but it is in Portland Stone rather than the more common Jurassic Limestones...