(Reuters) - British lender Metro Bank Plc (>> Metro Bank PLC) raised 278 million pounds by selling new shares to investors and also generated a pretax profit in the first half of the year.

Metro Bank, the first new high street bank in Britain in over 100 years when it launched in 2010, said the proceeds of the share placing would be used for growth and to replace funds used for its acquisition of a mortgage portfolio last month for 597 million pounds.

"The fact that we've actually raised 10 pct of the stock at the market price with no discount is a fantastic result. We were massively oversubscribed," Chief Executive Craig Donaldson told Reuters.

The lender, which offers retail, business and private banking, said underlying profit before tax was 6 million pounds in the six months ended June, compared with a loss of 13 million pounds a year earlier, driven by growth in lending and customer deposits.

Metro Bank, which listed in London in March last year with the aim of challenging Britain's big lenders, boosted its loans and deposit book, shrugging off concerns over slowing economic growth, a faltering housing market, high levels of consumer debt and rising inflation.

Rival Virgin Money (>> Virgin Money Holdings (UK) PLC) flagged a weaker housing market and pressure on margins on Tuesday, adding to signs of tougher trading for British lenders.

Metro shares traded 4 percent higher at 36.25 pounds by 0930 GMT and have risen from a flotation price of 20 pounds last year.

Britain's banking sector is dominated by the established might of Barclays (>> Barclays), HSBC (>> HSBC Holdings), Lloyds Banking Group (>> Lloyds Banking Group), Nationwide (>> Nationwide Building Society), Santander UK (>> Banco Santander) and Royal Bank of Scotland (>> Royal Bank of Scotland Group).

"In a small island with a lot of people, to have 6 banks dominate the market cannot be good for competition... it's important that we have growing organisations challenging the cartel of the big banks," Donaldson said.

John Cronin, analyst at Goodbody, said the placing will boost Metro Bank's core capital ratio by 590 basis points.

"Executing the transaction at yesterday's closing price will be likely welcomed by existing investors – though more capital will be needed in time," Cronin said.

(Reporting by Noor Zainab Hussain in Bengaluru and Dasha Afanasieva in London; Editing by Sunil Nair/Keith Weir)

By Noor Zainab Hussain and Dasha Afanasieva