Norwich Union (NU) is to close its Cambridge office, in a move that will affect more than 70 policy administration staff.
The office, at 10 Downing Street, is subject to a compulsory purchase order and the company must vacate the building by 12 April.
The insurer has decided not to relocate to another office, but to divide up the work among other branches.
Last Thursday (8 Novem-ber), staff were told their positions would no longer be available from April and the office was closed for the day.
An NU spokeswoman said: "The interests of staff were put first and they were escorted to a meeting.
"We will do everything we can to ensure they find new jobs elsewhere in CGNU.
"Those who can't be found new positions will receive redundancy payouts."
The spokeswoman added there could be no guarantees there will not be further redundancies at Norwich Union.
She said the business was "constantly under review".
This is the latest in a series of redundancies by insurers and their partners in the past few weeks.
Last week, AXA announced plans to lay off 100 managers and loss adjuster GAB Robins recently axed 70 staff.
Norwich Union has already laid off dozens of staff this year. In June, the insurer closed its travel and leisure division in Croydon, with 40 redundancies.
In September, five staff at Norwich Union's Oxford branch were forced to reapply for their jobs for the second time.
Norwich Unions' business has been undergoing restructuring since the company merged with CGU last year.