NS&I raised the rate on its Direct Saver from 3.65% to 4% and its Income Bonds from 3.65% to 4%.

The Government-backed savings provider did not publicly announce the changes.

Sarah Coles, head of personal finance at Hargreaves Lansdown, said the lack of announcement was likely due to avoiding straying into politics.

She said: “These small rises, which put them significantly under the best on the market, are highly unlikely to be designed to tempt more savers. If it was in the cash-attracting business, we would have seen much bigger jumps, to more attractive rates. Instead, it’s likely to be a sign that NS&I was keen to stem a flow of savers pulling cash out of the institution, so it has some relatively healthy numbers to report in July.

“The institution always has to balance the need to raise money against the need to offer value-for-money for taxpayers – while not distorting the savings market as a whole. It’s safe to say that these rates amply reflect its aim to be ‘good enough but not too good’.”

NS&I’s new 3-year fixed-rate British Savings Bonds went on sale in April offering interest of 4.15% gross/AER. This rate was raised to 4.5% last week.

The bonds are designed to help boost investment in the UK and increase government revenue from its provider NS&I.

The British Savings Bonds are new three-year, fixed-rate issues of NS&I’s Guaranteed Growth Bonds and Guaranteed Income Bonds. They offer savers a guaranteed interest rate fixed over three years for investments between £500 and £1 million.

For all savings products from NS&I the money is 100% guaranteed backed by the Treasury.

In the Spring Budget it was announced that NS&I’s Net Financing target for 2024-25 has increased to £9 billion (in a range of +/- £4 billion either side of this target).

NS&I has more than 24 million customers.