Lost Johns' Cave is an extensive cave system on Leck Fell, Lancashire, England. With its three major vertical routes it is a popular place to practise single-rope technique because of the opportunity for exchange trips. Also it can be safely visited on wet days because many of the pitches can be rigged out of the water. It is an important part of the Three Counties …Lost Johns' Cave is an extensive cave system on Leck Fell, Lancashire, England. With its three major vertical routes it is a popular place to practise single-rope technique because of the opportunity for exchange trips. Also it can be safely visited on wet days because many of the pitches can be rigged out of the water. It is an important part of the Three Counties System.