LONDON - Qatar Re, a unit of Qatar Insurance, has agreed to buy UK motor insurer Markerstudy's underwriting businesses for an undisclosed sum, Markerstudy said on Wednesday.

The deal for Gibraltar-based Markerstudy Insurance Company, Zenith Insurance, St Julians and Ultimate Insurance is expected to complete in the first half, Markerstudy said in a statement and will see Qatar Re take on 750 million pounds ($1.02 billion) in gross written premiums.

After the deal is completed, Markerstudy will no longer underwrite insurance and will instead focus on its role as a managing general agent.

($1 = 0.7356 pounds)

(Reporting by Carolyn Cohn; editing by Simon Jessop) ((carolyn.cohn@thomsonreuters.com; 44 207 542 6320; Reuters Messaging: carolyn.cohn.thomsonreuters.com@reuters.net))