Many NatWest customers with a flexible 'Foundations' mortgage are angry. The mortgage was marketed as being the perfect way to make overpayments but then to also be able to borrow again for large projects, such as a building extension.
But this week NatWest told some customers that following an annual review of their account, their borrowing facility has been cut.
Money Box has found the original press release from when the mortgage was launched, 10 years ago.
It says customers may 'borrow up to 90% of their property's value and can raise raise the borrowing back up to that level at any time during the life of the mortgage'.
But borrowers appear to have been caught out by small print which in fact allowed NatWest to review their level of borrowing annually.
Money Box listeners Susan and Steve Hill have been told their credit limit has been cut by £60,000. They had used their savings to over pay their mortgage on the understanding they could draw on the funds again when they needed to.
They say they had intended to use the savings for the expansion of their small business, and to send their son to university. But now they do not have access to this money.
The programme talks to mortgage broker David Hollingworth from London & Country about who else might be vulnerable.
This item was first broadcast on Radio 4's Money Box on Saturday, 12 December 2009