Earl Shilton, the Leicester-based mutual, has slashed the LTV on all its products to 50% due to over-demand.
It was previously 90% for introduced business and 95% for direct.
A spokeswoman for the mutual says that the recent increase in demand has resulted in case processing taking up to a month instead of its usual 10-day turnaround.
She says: “This isn’t acceptable.”
She adds: “The problem is that when you’re a small society you can easily get a bad reputation, so we’d rather slightly close the door to business now and reopen it in due course.”
But she says that she expects the reduction to have a minimal effect since around 75% of the mutual’s business is below 75% LTV due to its higher lending charge.
Intermediaries generate 45% of Earl Shilton’s mortgage business, which totalled £64.3m for the 12 months to March 2007.