BGL Group, the owner of price-comparison site Compare the Market, has bought personal injury specialist Minster Law in what is described as the biggest outright sale of a law firm to date.

Although the amount involved is undisclosed, the deal is expected to mean a multi-million-pound windfall for Minster Law chairman Adrian Christmas (pictured, left), who is listed in company accounts as the sole director and shareholder of the firm’s parent company.

As well as Compare the Market, made famous by its adverts featuring a meerkat, BGL has a claims management company and insurance firm among its businesses.

It is understood that BGL Group and Minster Law have enjoyed a long working relationship through the payment of referral fees for personal injury cases.

Speculation over a proposed takeover has been rife for several months, and the deal has been accelerated due to last month’s ban on referral fees.

The Solicitors Regulation Authority has spent more than a year analysing the application for an alternative business structure and is now satisfied it is compliant with regulations.

Executive director Samantha Barrass (pictured, right) said: ‘It has been necessary for the process to involve a very detailed consideration of Minster Law's application as it has a complex ownership structure.’

Minster Law, which is based in York and Wakefield, has grown rapidly since it was formed in 2006.

The firm now has a headcount of more than 800 people, of whom around 200 are fee-earners. It handled more than 40,000 personal injury claims in the last financial year.

Turnover increased by 27% in the 2011/12 financial year to £104m. This was turned into profit before tax of £3.8m - more than double the profit posted the year before.

Established in 1992, BGL Group is now one of the UK's largest personal lines insurance groups.

Revenues for 2012 increased from £354m in 2011 to £418m. During the same period profit jumped from £52.8m to almost £65m.

Its stable includes claims management company Advanced Claims Management and insurance brands including Bennetts, Junction and Fusion.