An independent insurance firm is set to be bought by a French mutual group which handles €15.5bn (£12.3bn) of premiums a year.

Sterling Insurance Group, based in Kings Hill, near West Malling, has been sold to Covéa after an agreement was reached with founder and chairman Nicholas Cooper.

The buyer is one of the largest insurers in France providing a wide range of life and non-life insurance products through three brands – GMF, MAAF and MMA.

It also operates in a number of other countries, including the UK, Italy and the US.

At the end of 2013, it had €10.6bn (£8.4bn) of capital and a solvency ratio of 405%, giving it one of the strongest cash flows of an insurance group in Europe.

The deal, the value of which has not been disclosed, will see Sterling become a sister company of Covéa’s existing UK insurer, Covéa Insurance.

Jobs numbers are not likely to be affected by the deal, which will be completed after regulatory approval, which can take up to three months.

In a statement, the Sterling executive team said: “While this announcement reflects the start of an exciting new chapter for Sterling, it’s important to be clear that nothing will change in the short-term not least because the deal is still subject to regulatory approval.

“Once the acquisition is complete, Sterling will continue to be run as a separate entity within the Covéa group with the existing directors and senior management remaining in the business.

“This announcement has no impact on our business relationships or day-to-day operations. It’s very much business as usual.”

As well as its Kings Hill base, Sterling Insurance has offices in Surrey, Birmingham and Manchester.

The company was formed in 1994 following the acquisition of Consolidated Insurance Group Ltd by GE Capital.