NORTHERN Rock remained tight-lipped last night over reports it had borrowed a further £5bn from the Bank of England.

News spread yesterday that the stricken mortgage lender's borrowing from the Bank of England had risen to almost £8bn since the central bank stepped in to offer emergency funding two weeks ago.

Economist Simon Ward examined the Bank's weekly accounts, which showed that in the past fortnight its assets had increased by £14.3bn, including £7.75bn classified under "other assets".

He said that figure was likely to include the Bank's "lender of last resort" support for Northern Rock.

"It is possible that other undisclosed activities have contributed to the increase, but the latest figures will fuel speculation that the Bank has been forced to extend massive support to the troubled mortgage lender," said Mr Ward, an economist at fund manager New Star.

But Newcastle-based Northern Rock and the Bank of England yesterday refused to comment on Mr Ward's findings.

A spokesman for Northern Rock said: "We are not providing details of our standby facility with the Bank of England in relation to drawdown or repayment.

"We remain solvent and solvency is the key basis on which the Bank of England agrees to make the standby liquidity facility that's available."

Mr Ward was accused yesterday of unnecessarily fuelling speculation surrounding Northern Rock's borrowing.

Anthony Platts, an assistant director at the Teesside office of investment management firm Wise Speke, said: "He (Mr Ward) is putting two and two together and making four in his opinion.

"In many ways it is a case of 'so what '- if Northern Rock has borrowed £8bn from the Bank of England then so what, the Bank of England doesn't lend to anyone unless they are solvent."

Northern Rock's shares, which had staged a small rally in recent days after it revealed it was in talks about a number of prospective deals including a takeover, slipped by more than seven per cent yesterday to 179.20p.

The stock has lost more than 70 per cent of its value in just over two weeks. Northern Rock, one of the region's most important financial institutions, first revealed it had been forced to apply to the Bank of England for emergency financial support on September 13. Since then, anxious customers have withdrawn £2.5bn from their accounts.

The company yesterday dismissed a report in the Financial Times that it had distributed almost £40m in dividends to holders of preference shares on September 21.