Fears were raised yesterday that more than two million home owners could face higher mortgage bills after NatWest became the first lender to increase repayments for existing customers. Daily Telegraph

NatWest, one of the country’s largest lenders, wrote to 15,000 customers with offset mortgages over the weekend to tell them their rates were going up from 6.2% to 6.45% with immediate effect.

This is the first time this year that the credit crisis has led to existing – rather than new – borrowers being affected by increased rates.

Last night Kent Reliance Building Society also hit some of its existing mortgage customers with a substantial rate increase, putting up its standard variable rate from 7.34% to 7.59%.