Barclays customers are experiencing intermittent errors with payments and transfers for a second day after serious IT problems that also affected the bank’s app and online banking.

Customers have told the BBC they are unable to make essential transactions, ranging from buying baby milk to completing a house move.

Barclays said on Saturday that cards and cash machines could be used as normal – though some customers have said this is not the case.

A Barclays spokesperson said the bank is “working hard to fix the issue” and that it will “ensure that no impacted customer is left out of pocket”.

The outage began on Friday, which was pay day for many people in the UK, and the deadline for self-assessment tax returns.

Barclays has not explained the cause of the IT problems or how many people are affected.

On Saturday afternoon, Barclays’ website indicated that problems persisted with its app, and warned that customers may face issues making and receiving payments.

The website also told customers that the bank may not be able to assist with all queries in branches “due to issues we’re facing”.

Businessman Tim Horner from Petworth, West Sussex said on Saturday he has been unable to pay his staff or HMRC.

He told the BBC that he has had “multiple calls” from people trying to make payments to his ecommerce platform, saying that their payments are “being refused”.

“I have lost thousands of pounds due to my online store being unable to receive payments as we have a Barclays account,” Mr Horner said.

Ruth, 39, a self-employed cleaner, told BBC News she had been trying to access money with her partner from their savings account for several hours so she could buy milk for a baby and food for five other children she is looking after at home.

“We need the money to do shopping, our money is all in savings,” she explained.

“I’ve got my granddaughter here who’s 11 months old, also a one-year-old, two-year-old, 12-year-old, 13-year-old, 15-year-old all at home.”

She said she had been able to get some help from her teenage daughter, but said others might not be so fortunate.

“There could be many single mums in the same situation with no access to money,” she told the BBC.

Barclays is one of the UK’s largest banks, with over 20 million UK retail customers. It says it processes over 40% of the UK’s credit and debit card transactions.

Website downdetector, which monitors outages, says thousands of people have flagged problems at the bank. On Saturday morning, it showed more than 4,000 issues had been reported with Barclays, more than double the number reported on Friday.

A family told the BBC on Friday they could not move into their new house because of the outage, branding the situation “ridiculous”.

Scott, 27, and his wife, who is four months pregnant, said they had sold their house on Friday morning, but the money for their new home had not gone through yet due to the problems at Barclays.

Scott told BBC News they were effectively homeless, and had been left waiting in their car at a service station in Horsham, West Sussex.

“Because the system is down, the money can’t go through,” he said.

“We just have to sit and wait.”

Taking to social media, one mother said she could not buy milk for her baby due to the issues at Barclays.

“My four-month-old is out of milk powder and screaming for a feed and I still haven’t been paid,” she said.

“I’ve been in tears for hours.”

Friday was the deadline for self-assessment tax returns, and some customers have said the outage has left them unable to make payments to HMRC.

Earlier on Friday, HMRC warned that millions of people have still not filed their self-assessment tax returns, and warned of £100 fines for those who did not meet the deadline.

However, in statement to the BBC, HMRC said it was “working closely” with Barclays to minimise any impact on customers filing their self-assessments.

A spokesperson added: “Our services are working as normal, so customers will be able to file their returns on time.

HMRC added that Barclays issues “will not result in late payment penalties as they don’t apply until 1st March”.

In a statement, Barclays said: “We’re in direct contact with HMRC and they are aware of the technical issues with our system.”

It added: “We will ensure that no customer is left out of pocket because of delayed payments caused by this incident.”

It is not the first time banking app customers have been left unable to access funds or make payments.

PayPal suffered a brief but notable outage in November that impacted customers globally across a number of its products, including its cryptocurrency services and popular US peer-to-peer payment app, Venmo.

Thousands of UK bank customers were affected by payment problems with some of the biggest lenders in June last year, with banks including HSBC, Nationwide, Barclays and Virgin Money all impacted by issues with a system that facilitates payments between individuals and companies.

Some cash-strapped customers continued to feel the effects of the issue for days afterwards.

BCS, the Chartered Institute for IT, said the problems with Barclays showed the importance of robust computer systems.

“Once again this goes to show how cyber-security and digital resilience is so tightly integrated into our lives,” said Dan Card, BCS’ cyber-security expert.

A Barclays spokesperson said the bank was “incredibly sorry for the ongoing technical issues” affecting customers’ accounts.

“Some may see an outdated balance, and payments made or received may not show,” they said.

“We’re working hard to fix this issue, and customers should not try to make the payment again.”

“Customers can use their cards and withdraw cash, and as soon as these remaining issues are resolved, we’ll let our customers know,” the spokesperson added.

Additional reporting by Liv McMahon