Tesco is stepping up its move to take advantage of the banking crisis and positioning itself for a possible purchase of Northern Rock.

The supermarket today changed the name of its personal finance arm to Tesco Bank, and said that it will soon start selling current accounts from in-store branches which offer the full range of banking services.

It also produced separate results for the bank for the first time — a profit of £115 million on sales of £420 million in the first half of the year.

Chief executive Sir Terry Leahy said: “I think Tesco Bank sets out a stall for the future of our business. It will be a bank for Tesco customers and there will be more products soon.”

He declined to say whether Tesco is interested in acquiring Northern Rock, saying he would “focus on organic expansion” initially.

In Whitehall and the City, however, there is a growing expectation that Tesco may buy the collapsed Newcastle bank if the Government moves to return it to the private sector ahead of an election.

Tesco Personal Finance was originally a joint venture with Royal Bank of Scotland.

Tesco took full ownership last year, believing that customers angry with high street banks would trust it with their savings and other finances.

It already has 300,000 customer accounts and is the seventh-biggest issuer of credit cards in the UK.

The bank's Tier 1 capital ratio — an industry measure of financial strength — stands at 12.6%, a level that far outstrips most rivals.