Royal & SunAlliance (R&SA) has announced plans to close its offices in Ipswich and Hinkley, Leicestershire with the loss of 348 staff.
The Ipswich branch, which has a total of 240 staff will close at the end of 2004 while the Hinkley branch, employing 108 staff, will close in April next year.
An R&SA spokesman said the majority of staff in both offices would be made redundant, though there will be some "redeployment opportunities".
AXA won the competitive tender and will replace R&SA from 1 February 2004.
Last week, Insurance Times reported that R&SA's deal to underwrite £80m-£90m premium of household insurance for HSBC is under review.
Earlier this year it was reported that R&SA would cease to underwrite a £400m premium household book for Halifax.
R&SA has said that it is backing away from unprofitable books of business.