Aug 26 (Reuters) - Office provider Regus Plc reported an 8.1 percent rise in first-half revenue, propped by strong demand at its established centres.

Regus, which rents out meeting rooms, business lounges and offices, expects to open at least 450 business centres this year, up from its previous guidance to touch at least 300, the company said on Tuesday.

Revenue rose to 804.7 million pounds ($1.3 billion) in the six months ended June 30, from 744.7 million pounds a year earlier. Excluding the adverse effect of a rising British pound, revenue grew by 16.9 percent.

Suffering a blow from the strong pound, first-half pretax profit fell marginally to 31 million pounds.

($1 = 0.6028 British Pounds) (Reporting by Esha Vaish in Bangalore; Editing by Gopakumar Warrier)