Trenwick International has put its London-based non-Lloyd's business into run-off.
The move mainly affects its liability business, including cover for latent defects, engineering and warranty and credit and bonds.
Other business, comprising property and cargo and general aviation has been moved to Trenwick's Lloyd's operation. Commercial property is expected to follow.
Liability insurance made up about 10% of Trenwick's business, which generated up to £500m of premium income.
The company had been fighting for its future after downgrades to its parent group by ratings agencies made it less attractive to brokers.
The Lloyd's operation has until 6 December to renew a letter of credit to support next year's underwriting.
There will be 11 redundancies from the company's London offices as a result of the move to run-off the business. Markets are due to be informed tomorrow.
Berkshire Hathaway's interest in the group's aviation business, made via its Syndicate 2750, remains unchanged. Trenwick International's general aviation business is being moved to its Syndicate 839.
