Mike Waterson, a founding member of influential English folk act the Watersons, died June 21 at a hospice in Scarborough, England, after a protracted battle with cancer. He was 70.The Watersons — Mike, sisters Norma and Elaine (better known as Lal) and family friend John Harrison — was founded as a skiffle act in the mid-’50s but soon moved on to interpreting English folk music. In 1958 the group founded its own trad music club; by the mid-’60s it was established as Folk Union One at a pub in the act’s hometown of Kingston-upon-Hull. In 1965 the Watersons were one of four groups featured on the important omnibus set “Folk-Sound of Britain,” issued by the important folk label Topic. Three celebrated albums showcasing the group’s close harmonies followed. In 1968 the band came apart, but Mike and Lal Waterson went on to collaborate on an acclaimed duo project, “Bright Phoebus” (1972). Reformed in 1972, the Watersons played in several different configurations, including a latter-day edition that included Norma’s husband, the noted folksinger-guitarist Martin Carthy, and Norma and Carthy’s daughter, fiddler Eliza Carthy. Mike Waterson also recorded as a solo artist and as a member of the ’80s folk supergroup Blue Murder, which also included core members of the late-period Watersons. He made his last appearance with the family act in late 2010. Waterson is survived by his wife, singer Ann Waterson, and four children.