Carol Wallace, the partner of City of York Council leader Rod Hills, has died at the couple's York home.
Police were called to the address in Huntington Road last night and said today they were investigating her sudden death as a "routine inquiry".
Staff and councillors were today in shock at the death of Coun Wallace, who was a Bishophill councillor and executive member for economic development.
David Atkinson, acting chief executive, said: "This is devastating news and everyone at the council is deeply shocked.
"Our thoughts are with Coun Hills, her partner, and with Coun Wallace's family at this time."
Detective Inspector Phil Metcalfe of York Police said: "Police at York are investigating the death of a woman at her home in York.
No further details of the incident are available at this time as inquiries are ongoing.
"This matter is being treated as a routine police inquiry."
Coun Wallace worked as a lecturer in language and linguistics at the University of York.
She also worked as an admissions tutor for undergraduate students coming into the department.
Hilary Layton, university spokeswoman, said: "Carol Wallace worked at the university for a long time and had many friends and everyone is devastated.
"We are all shocked and saddened."
janet.hewison@ycp.co.uk
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