National Savings and Investments (NS&I) today sought to reassure consumers it could meet demand for its inflation-beating savings product following a scramble to invest in it.
The Government-backed group said its Index-linked Savings Certificate, which it relaunched last week after a 10-month absence, had proved "very popular", with its call centre struggling to keep up with demand at some points.
It added that interest in the product, which helps people stop the value of their savings from being eroded by inflation, had spiked on Saturday afternoon following a piece about it on BBC Radio 4's Money Box programme.
But despite some commentators predicting demand would be so strong that the certificates would be sold out within weeks, NS&I today insisted they would be available for "some time".
The last time the product was launched it was on sale for only three months before it became so oversubscribed that the group had to pull it.
An NS&I spokeswoman said: "We have allocated set funds for it and we expect to keep the product on sale for some time."
She added that in order to meet its Government-funding target for the year, NS&I would have to take in around £14 billion of consumers' money, and it expected savings certificates to account for a significant proportion of this.
In a bid to manage demand for the product, NS&I has said it must be taken out directly with the group, either by telephone, on the internet or by post, and the certificates are not available through the Post Office.
It is also only offering the certificates for a five-year term, rather than a three or five-year term as was previously the case, and each person can invest a maximum of £15,000 into them.
Demand for the product has soared as a result of high inflation, which has left savers struggling to find accounts paying a high enough interest rate to enable them to make a real return on their money.
A basic rate taxpayer needs to earn returns of 5% to stop the value of their savings eroding once tax and inflation are taken into account, based on March's Consumer Prices Index figure of 4%, while higher rate taxpayers need to earn interest of 6.67%.
The Inflation-linked Savings Certificates pay a tax-free return each year based on the Retail Prices Index (RPI) measure of inflation, plus interest of 0.5%, meaning savers are making a return on their money in real terms.
Two other providers also offer products that pay inflation-linked returns, although unlike NS&I these do not come with the 100% Government guarantee, but savers still have up to £85,000 of their money protected by the Financial Services Compensation Scheme.
BM Savings, which is part of Lloyds Banking Group, offers returns linked to RPI plus interest of 1.5% a year on its five-year product and interest of 0.75% a year on its three-year one.
Yorkshire Building Society also offers a five-year bond which pays returns of RPI plus 0.29% a year.