The government’s motto may be that a mortgage is for life, not just for new homes, but lenders and brokers think differently. They say long-term mortgages are inflexible, expensive and out of sync with modern day living. (These loans also do away with lucrative arrangement fees for both parties.)

But for the many homeowners drawing dangerously close to the end of cheap mortgage deals, just as lenders are snatching away any remotely attractive new rates, the idea of a loan that provides a steady rate for up to 25 years might sound like quite a good bet. Borrowers know how much they will have to pay for the period. They are saved the hassle and expense of switching to a new mortgage every couple of years and the gamble of whether their new rate will be higher or lower next time.