While the economic turmoil wrought by the coronavirus pandemic has left some people in Britain counting every penny, the country’s central bank is apparently having trouble keeping track of billions of pounds.

A parliamentary report released Friday said that 50 billion pounds (about $67 billion) of paper money is “missing” from the country’s cash supply and that the Bank of England “seems to lack curiosity” about where it’s all gone, according to a report by The New York Times.

Of the more than 70 billion pounds worth of bills in circulation in Britain, the report found that only about a quarter was being spent in stores and on other purchases. That leaves the majority of those bills — which by design are not traceable — unaccounted for.

The 50 billion pounds in cash may be hidden away in unreported household savings, squirreled away for a rainy day or is being used for more nefarious purposes, Parliament’s Public Accounts Committee said in the report, calling on the Bank of England to investigate.

“50 billion pounds of sterling notes — or about three quarters of this precious and dwindling supply — is stashed somewhere but the Bank of England doesn’t know where, who by or what for — and doesn’t seem very curious,” said Meg Hillier, the lawmaker for the Hackney South and Shoreditch areas of London and chair of the committee that produced the report.

The Bank of England hit back at the suggestion it was taking a laissez-faire approach to the issue.

“It is the responsibility of the Bank of England to meet public demand for bank notes. The Bank has always met that demand and will continue to do so,” a spokeswoman from the central bank said in a statement Friday.

“Members of the public do not have to explain to the Bank why they wish to hold bank notes. This means that bank notes are not missing,” the bank’s statement said.

The pandemic has led to a slump in cash payments, but demand for bills has risen in recent years and the pandemic has accelerated that trend, the report said. The value of paper (and polymer) bills in circulation in Britain hit a record high in July of 76.5 billion pounds.

One reason might be that interest rates, which have been low for years, were cut even further this year to boost the British economy.

“With interest rates so low, it doesn’t really matter whether you keep money in the bank or keep it in cash,” said Andrew Sentance, a senior adviser at Cambridge Econometrics and a former member of the Bank of England’s monetary policy committee. The current base rate of 0.1% means “a lot of people will have more cash in their wallet than they usually have.”

Still, the public accounts committee — which scrutinises the economy and spending — is unconvinced by that explanation and is concerned that a substantial proportion of the 50 billion pounds has been siphoned off and is being used for illegal activity such as money laundering in the shadow economy, whether in Britain or abroad.

“Are more of us putting money under the mattress because of COVID? It would have to be a lot of us doing that,” Hillier said in an interview Friday, adding that the gap between notes in circulation and those actually being used “must be linked to crime.”

The Parliamentary committee hopes an investigation by the Bank of England may shed some light, if not on where it is being held, then at least on the factors behind the increase in demand for cash.

For its part, the Bank of England said that the amount of paper money being used for transactions in Britain — around 20% to 25% of all cash in circulation — is broadly in line with other major economies.

The money is “stashed somewhere but the Bank of England doesn’t know where, who by or what for — and doesn’t seem very curious,” Meg Hillier, chair of the House of Commons Public Accounts Committee (PAC), which oversees government finances, said in a statement. “It needs to be more concerned about where the missing £50 billion is,” she added.

The Bank of England immediately pushed back. “Members of the public do not have to explain to the Bank why they wish to hold banknotes. This means that banknotes are not missing,” a spokesperson said in a statement, adding that the central bank would continue to meet public demand for notes.

Despite the increased use of digital payments, demand for cash has risen in most advanced economies since the global financial crisis, according to a 2018 report by the Bank for International Settlements. This has been partly driven by lower interest rates, the report said, which have diminished returns on savings held with banks.

“We are seeing the increasing use of cash as a store of value, as opposed to for transactional purposes,” chief cashier at the Bank of England Sarah John said in testimony before the Public Accounts Committee in October. Worries about the strength of financial institutions since the 2008 crisis have also contributed to this, she added.

And while there was a sharp decline in demand for notes and coins during the peak of coronavirus lockdowns this year, it has since recovered, with people stockpiling even more cash at home as a result of the pandemic.

The number of notes in circulation in Britain reached a record high of 4.4 billion in July, with a total value of £76.5 billion ($103 billion), according to a September report by the National Audit Office (NAO), which monitors government spending. This compares with 1.5 billion notes worth about £24 billion ($32.3 billion) in 2000.

At the same time, the volume of cash payments has declined, a trend likely to accelerate because of the pandemic. A decade ago, cash was used in six out of 10 transactions; last year it was less than three.

The Bank of England estimates that between 20% and 24% of the value of notes in circulation are used for cash transactions, with a further 5% held by UK households as savings.

“Little is known about the remainder, worth approximately £50 billion, but possible explanations include holdings overseas for transactions or savings and possibly holdings in the UK of unreported domestic savings or for use in the shadow economy,” the NAO said in its report.

It recommended that the central bank, working with other public authorities, improve its understanding of what is driving the increase in demand for notes and who is holding the £50 billion.

“This work might help inform wider policy, for example on tax evasion,” it added.

The NAO report cautioned that the dwindling use of cash could increase the risk of financial exclusion if businesses stop accepting cash due to rising costs associated with declining volumes. Just over a million UK adults do not have a bank or building society account, the report said, citing data from the Financial Conduct Authority.

“There is definitely a link to more deprived areas still relying on cash a lot more than in some city centers,” John told the PAC.

There are currently five public bodies responsible for administering or overseeing Britain’s cash system, including the Bank of England, the Treasury, the Royal Mint, the Financial Conduct Authority and the Payment Systems Regulator.

The UK government said in October that it is considering giving the Financial Conduct Authority the overall responsibility for the retail cash system “given its existing regulatory role and consumer protection objective.” It also outlined plans to ensure people continue to have easy access to cash.