Nelson Mandela remains 'critical but stable'

Nelson Mandela's condition is "improving" according to former South African President Thabo Mbeki, but a family member says his condition remains "critical but stable.''

The former leader's grandson, Ndaba Mandela, said he is responding during visits.

Earlier this week, President Jacob Zuma said the 94-year-old remained "critical but stable" in a Pretoria hospital.

Mike Wooldridge reports.