"Can you rely on a quote from a lender? The answer is no," Rob Clifford, chief executive of Mortgageforce, told the Times of London.

The luxury of considering a deal is evaporating for borrowers, The Times reported. Sitting back to "mull over a mortgage offer" includes the risk that rates will go up, mortgage broker David Hollingworth of London and Country said.

"It is a challenge to keep on top of all the changes," he said. "We are working extended hours to get applications through before rates are withdrawn."

The pressure on lenders has caused some to withdraw from the market, the report said. Other brokers are encouraging borrowers to nail down a rate as soon as they can.

"A rate available on Friday could be gone by Monday," Hollingworth told The Times.