The news had nothing to do with rising interest rates; the cause was First Active's decision to change the rules on its current account mortgage.

First Active pioneered this new-style mortgage as a way for customers to slash their interest bills. The idea is that money held in a current account is netted off against your mortgage, so you only pay interest on the difference.

Up to now, First Active has given customers a choice about how to use the interest savings. With the standard option, they could use the money to cut the monthly mortgage payment. With the planned option, they could stick with the original payments but reduce the overall term of the mortgage.

Now First Active wants to scrap the standard option, sending the payments on our Limerick reader's mortgage from 600 a month to 1,172.

This is a bitter blow at a time when the family is expecting a new baby and the mother plans to stop working outside the home after the baby's birth.

"We owe 185,000 on the mortgage and leave 50,000 of savings in the current account to keep the interest down, " the reader says. "Our payments of 600 a month used to be based on a net 135,000, the difference between the two amounts.

But now First Active wants to base the payments on the full 185,000 mortgage."

The result is that the family will have to eat into its 50,000 nest egg to meet the higher payments. "Our financial flexibility is being greatly reduced, " the reader says.

"My wife is going on maternity leave soon, so First Active could not have picked a worse time to spring this on us. We were building up the money in the current account as a contingency fund, but if we're forced to make higher capital repayments, we won't have nearly as much at our immediate disposal."

The advantage of making higher payments is that our reader's mortgage should be paid off years ahead of its original 20-year term. But he says he could have achieved the same result under the lower standard payments.

"My goal was to keep building up the money in the current account while chipping away at the mortgage so that, maybe in 10 years time, there would be about 90,000 left in each, " he says. "At that stage, I'd have effectively paid off the mortgage but still have 90,000 at my disposal to use as I please. It would be like an equity release mortgage but without the hassle."

The reader is upset that, just two years into the mortgage, First Active is trying to move the goalposts.

"The mortgage contract allows them to vary the terms and conditions, but this is a pretty substantive change, " he says.

"First Active wants me to agree to switch to the planned payments option by 1 July, but I've no intention of signing the form they've sent out.

I'm not going to let this one lie."

A spokesman for First Active said that only a handful of customers would be affected by the scrapping of the standard payment option.

"The core proposition with the current account mortgage is to allow customers save interest and to reduce the term, " he said.

"The standard option doesn't get the term down, so very few customers went for it. It tended to cause confusion for customers trying to understand the benefits of a current account mortgage.

The vast majority of our customers won't have a problem with what we're proposing."

He advised our reader to try to sort out the problem at his local First Active branch. "The change is something we believe is in most people's interests, but we will do our best to accommodate individual customers, " he added.