Long-term mortgage rates have been rising, putting further pressure on borrowers.

That limits its ability to cool the housing market, since long-term mortgage rates, the key to cooling the economy, are beyond its immediate control.

This undermined the financial strength of many associations that were also offering customers long-term mortgages at fixed rates of interest.

Borrowers have shied away from locking themselves into long-term mortgages partly because of the hefty charges levied when you try to end the contract early.

As a consequence many homeowners are trying to protect themselves from rate rises by locking in to long-term mortgages at interest rates of 6 per cent or more.