Stuart Hyde, who was an assistant chief constable at West Midlands Police, is being treated for a viral infection.
Mr Hyde, who was most recently the head of Cumbria Police, is co-director of the 4 Policing consultancy with Mike Pannett.
Mr Hyde, who was awarded the Queen's Medal, joined Avon & Somerset Constabulary in August 1983 and rose through the ranks to become a detective superintendent in West Yorkshire Police in 1997.
He was then promoted to the post of assistant chief constable of West Midlands Police in April 2004 and was given an honorary doctorate in 2009 at the University of Wolverhampton
His national responsibilities included the police use of DNA, creating the Child Exploitation and Online Protection centre and reducing crime against students.