Debevoise & Plimpton's London arm has acted on a £591m M&A transaction, advising opposite Lovells on a deal to create the largest underwriter on the Lloyd's Insurance market.

The New York-based firm has advised specialist UK insurer Catlin Group on the acquisition of its smaller rival Wellington Underwriting.

Debevoise has acted for Catlin since Ashurst corporate partner Jeremy Hill – who led on the deal – joined the firm in 2004. Hill was assisted by corporate associate Colin Scagell.

The deal, which was announced last month (30 October), is expected to close before the end of the year.

Lovells corporate partner Charles Rix, assisted by Nicola Evans, headed up a 10-strong team advising Wellington Capital, a longstanding client of the firm.

Rix commented: "It has been a very good deal for Wellington and Catlin. There are plenty of synergies between the two companies."

The transaction comes shortly after Debevoise in the US last month advised private equity firms Ripple-wood Holdings and Oak Hill Capital Management on the purchase of a majority stake in rental company RSC Equipment Rental from equipment company Atlas Copco, valued at approximately $ 3.4bn (£1.79bn).