A senior NHS official faced calls to resign over his links to a scandal-hit hospital trust where mothers and babies died.
Mike Farrar, who heads the body representing NHS trusts, was in charge of North West Strategic Health Authority (NWSHA) at the time of the failings at Morecambe Bay.
The Parliamentary and Health Service Ombudsman (PHSO) confirmed it was investigating complaints against the NWSHA.
James Titcombe, whose nine-day-old son Joshua died at Furness General Hospital, said Mr Farrar should consider his position as chief executive of the NHS Confederation.
He told the Independent on Sunday: