At the far end of Duke Street is Whirlpool chamber where a short sump (not free-diveable) gave access to cave divers into further passages known as Ireby II.

In early 2007, a system involving a primitive hand pump[5] and a mud dam to temporarily retain the water in an artificial lake in Duke Street allowed non-divers to enter this part of the cave.

[6] This facilitated the digging out of a passage in the roof of Whirlpool Chamber previously blocked by sand, to be dug out from both ends hence creating a bypass to the sump.

The prominent depression of Ireby Fell was marked as "The Cavern" on the first (1847) issue of the Ordnance Survey maps, though the early explorers could see little justification for the name.

Various digs were undertaken from 1932 onwards until in 1949 a small scar on the NW side of the shakehole gave access to a passage that reached the first pitch.