Individual ministerial responsibility is a constitutional convention in governments using the Westminster System that a cabinet minister bears the ultimate responsibility for the actions of their ministry or department.
ccording to Individual Ministerial Responsibility:

• Ministers are individually responsible for the work of their departments and are answerable to Parliament for all their departments activities.

• They are expected to accept responsibility for any failure in administration, any injustice to an individual or any aspect of policy which may be criticised in parliament, whether personally or not