(Corrects period end to December)
LONDON, Feb 20 (Reuters) - Nationwide, Britain'sbiggest customer-owned lender, said the number of customersopening new personal current accounts rose by 20 percent in thenine months to end December.
The increase helped Britain's third-biggest mortgage lendermore than double underlying profit to 539 million pounds ($901million) during the period.
Nationwide is seeking to challenge the dominance ofBritain's five biggest banks - Lloyds Banking Group,Royal Bank of Scotland, Barclays, HSBC and Santander UK ($1 = 0.5983 British pounds) (Reporting by Matt Scuffham; Editing by Huw Jones)