(Reuters) - Shares in Domino's Pizza (>> Domino's Pizza Group PLC.) jumped more than 10 percent on Tuesday after Britain's biggest pizza delivery firm reported a pick up in third-quarter sales, driven by online orders.

The company, a master franchisee of U.S. group Domino's Pizza Inc (>> Domino's Pizza, Inc.), said it expected full-year underlying profit before tax to meet market forecasts.

Group system sales in the 13 weeks to Sept 24 jumped 20.8 percent to 286.4 million pounds, with sales at UK stores open for more than a year rising 8.1 percent.

Online sales in its main UK market leapt 17.4 percent.

At 0720 GMT, Domino's shares were up 10 percent at 333.7 pence, after touching 343.9 pence, their highest since March.

The third-quarter performance marked an improvement from the first half of the year when total sales rose 10.5 percent.

The company said it would open 90 stores in Britain this year, citing strong demand for delivered food despite an uncertain consumer environment.

(Reporting by Rahul B in Bengaluru, Editing by Louise Heavens and Mark Potter)

Stocks treated in this article : Domino's Pizza, Inc., Domino's Pizza Group PLC.