From 1973 to 1996, Cooper was councillor for the Broadgreen ward. From 1996 to 2000, Cooper represented the Allerton ward, before in 1999 she switched to the Labour Party, becoming a partymate to former general election opponents Loyden, Howarth and Kennedy, and stood in the Netherley ward in 2000, though she did not win and left the council that year. She contested the European Parliament elections in 2004 for Labour in the North West.
