Savers are being advised to lock themselves into long-term savings bonds offering returns of 5 percent before they disappear.
The 5 percent figure is above the current inflation rate of 2 percent and so offers a useful hedge against rises in living costs.
However, finance industry experts warn that these best paying deals are likely to be removed in the coming days.
Interest rates on savings have remained relatively stable since last week’s Bank Rate cut, but experts believe it is only a matter of time until things change.
Rachel Springall, of analysts Moneyfacts, said: “Savers sitting on the fence to invest their cash with a fixed rate bond may wish to do so quickly, as the top rates are not guaranteed to be there for long.”
Moneyfacts data shows that a handful of one-year fixed bonds above 5 percent still remain on the market, while the leading two-year fix comes in at 4.91 percent.
The best three-year term is 4.71 percent, while the leading four-year term is 4.31 percent.
For the biggest returns, a saver putting down a £20,000 deposit in the leading five-year fixed bond of 4.55pc from Al Rayan Bank would earn £4,983 on maturity.
If the rate were to drop to 4 percent, the returns on the same £20,000 would fall by £630. If it were to drop to 3.55 percent, the interest payable would slump by £1,172.
Moneyfacts data shows so-called challenger banks are holding the top rate positions in the market, and one-year bonds continue to be the most popular options taken on by savers.
Ms Sprignall told the Telegraph: “Savers need to act now to grab a new deal, or they could be left disappointed.”
She added: “There may be presumptions among some savers that competition is lacking across fixed rate bonds, but that would be untrue.
“There have indeed been brands readjusting their position in the market to better manage the flow of funds or in a reaction to their peers dropping rates, but in contrast there are also brands very keen to grab the spotlight to draw in deposits.”
Shawbrook Bank said those nearing retirement age (55- to 68-year-olds) are neglecting the important role savings accounts could play for their retirement pots.
Adam Thrower, head of savings at Shawbrook, said: “Utilising long-term savings accounts now and in retirement is crucial for bolstering income.
“Despite awareness of their importance, too few near-retirees plan to use these accounts.”
However, he warned that people placing large sums in long term savings bonds face a tax bill on the interest. The tax free limit on returns is £1,000 for basic-rate rate taxpayers, just £500 for a higher rate taxpayer, and nil for those on a 45 percent rate.
To avoid tax on interest, savers can max out their £20,000 yearly Isa allowance, although the rates offered on cash Isas are typically below the market leading deals.
