Savills Private Finance, a broker, is offering to carry out the valuations when you book a mortgage for as little as £250 for mortgages up to £1m, against the usual £900 including Vat. Mortgages up to £2m will cost £500.

The broker has tied up with a leading surveyor and said its deal would apply to the majority of lenders, though some private banks were not participating.

Experts predict that the gloomy economic outlook and rising inflation will mean mortgage deals will continue to head upwards.

Many top deals have already been withdrawn. Lloyds TSB and mortgage arm Cheltenham & Gloucester repriced their entire ranges this week, in some instances rising by as much as 25 percentage points.

Someone who booked their mortgage rate six months ago could have got a two-year fix at 4.99% from West Bromwich building society — nearly 1 percentage point lower than anything now available.

One of the top deals at present is Loughborough building society’s two-year fix at 5.75% with a £649 arrangement fee.

Most lenders will let you secure a deal for six months. The advantage is that if rates rise by the time you remortgage, you can take the reserved rate, potentially saving you hundreds of pounds. However, if rates fall you are under no obligation to take the mortgage. Savills will help you choose another mortgage available at that time.

The same valuation can be used, although it will need to be “refreshed” at a cost of £80.

Mark Harris, managing director of Savills, said: “This mortgage rate hedge buys peace of mind for homeowners concerned about ever-rising mortgage rates. Even if you are not due to remortgage for some time, you can secure a rate now and then forget about it. When you come to remortgage, if rates have gone up you will be delighted that you took action now.”