The mortgage deals affected are those where new borrowers sign up for “fixed rates” – where the interest rate they pay is locked for a set period, usually two or five years.

Rates have been at record lows for many months. Any clear sign that they are on the rise will prompt fresh calls for borrowers to take out an ultra-low rate while they can.

Nationwide, the biggest building society, raised the rate on its cheapest two-year fixed deal from 1.19pc to 1.44pc. David Hollingworth of broker London & Country the brokers, said that while the increases announced to date were small they could easily “snowball” as lenders tweaked their rates in line with rivals.

“Although it’s not yet a seismic shift, this kind of repricing can pick up pace,” he said.

“Borrowers that have so far failed to take advantage of the ultra-low fixed rates may want to consider if now is the time to act. The Bank Rate, set by the Bank of England, is the barometer against which most household savings and borrowing rates rise and fall.

It is now expected to post its first increase in more than a decade, come next month.