By Jennifer Hill, Personal Finance Correspondent

LONDON (Reuters) - A war in the savings market has intensified, amid a global credit crunch that has hit Northern Rock and caused a string of lenders to raise their mortgage rates.

Savers are continuing to reap the rewards of the squeeze that has sent the cost of money shooting up without the Bank of England (BoE) lifting a finger, as institutions turn to savers to boost their cash-flow.

Rachel Thrussell, head of savings at price comparison service Moneyfacts.co.uk, said: "In times of base rate stability, it is more common to see rates stagnate or even fall, so it is unusual to see a trend of providers paying increased rates outside a base rate rise.

"With the credit crisis appearing to have rejuvenated the savings market as a by-product, savers should act fast and snap up the great deals on offer."

A host of new account launches has shaken up the market.

Sainsbury's Bank -- the long-standing No 1 Internet savings provider -- has been knocked off top spot by the launch of Bradford & Bingley's Internet saver paying 6.40 percent.

AA Financial Services has also introduced a new Internet account, paying 6.30 percent, while Icesave -- the Icelandic Bank which has long ranked highly in best-buy savings charts -- has increased the interest on its easy access account by 0.10 percent to 6.30 percent.

Building societies Yorkshire and Principality have upped their rates too -- by 0.25 percent and 0.10 percent respectively to 6.20 percent.