Nationwide customers have benefited to the tune of about £300 million in the last six months, the building society said today as it announced record first half pre-tax profits.

Britain's biggest mutual said its members had enjoyed better interest rates and lower fees and charges than those offered by its rivals in the first half to October 4. Last year's equivalent figure was £272 million, it said.

The Nationwide said pre-tax profits during the period had climbed 30% to £244.9 million against the same period last year while total assets had lifted 6.35 to £107.8 billion against the total in April this year.

The group made net advances of £7.4 billion, representing 13.7% of the market, and its mortgage retention levels were "excellent", with a 6.3% share of principal repaid.

Mortgage accounts in arrears were down 21% from October last year and the group had a 9.3% share of the retail savings market.

Gross credit card openings in the first half totalled 114,000, bringing the total number of credit card accounts to 742,000, with more than 900,000 cards in issue.

The group opened almost 300,000 new current accounts, up 17% on the same period a year before.

In July, the group unveiled plans to invest more than £300 million in its retail business during the next six years, refurbishing all its branches and agencies and installing more internet terminals and new systems in branches and call centres.

Chief executive Philip Williamson said the society's performance in the first half of the year had once again been "first class".

It had made record profits whilst also delivering the highest ever level of pricing benefits to its members, he said.

"In our core markets of mortgages, retail savings and banking services, we continue to punch well above our weight," he said.