What is "jack the lad"

n. (context British slang English) An irresponsible young man, seeking personal pleasure without regard to responsibilities. A rogue.

Jack the Lad were a folk rock/ electric folk group from North East England formed in 1973 by three former members of the most successful band of the period from the region, Lindisfarne. They moved from the progressive folk rock of Lindisfarne into much more traditional territory and were in the mid-1970s something of a northern counterpart to bands like Fairport Convention. They have also been seen as part of an important roots movement, rediscovering traditional Northumbrian music.