LONDON, Dec 21 (Reuters) - Insurance and reinsurance company XL Group has finalised a 2.53 billion pound ($3.95 billion) takeover of Catlin Group Ltd, operator of the biggest syndicate in the Lloyd's of London insurance market, the Sunday Times reported, citing a source close to XL.

Catlin told the market on Wednesday it had been approached by XL about a possible offer of 410 pence in cash and 0.130 share for each Catlin share.

The Sunday Times said the deal would be "broadly in line" with the terms outlined last week.

Catlin declined to comment on the article, while a spokeswoman for XL was not immediately available for comment.

($1 = 0.6398 pounds) (Reporting by Paul Sandle; editing by Abigail Fielding-Smith)