Barclays bank is experiencing intermittent errors with payments and transfers amid serious IT problems that also earlier affected its app and online banking.

Customers have told the BBC it is preventing them making essential transactions, ranging from buying baby milk to completing a house move.

Barclays says cards and cash machines can be used as normal – though some customers have said this is not the case.

The outage is occurring on what is 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 but has apologised and says it is “working hard to fix the issue”.

In the early hours of Saturday morning, Barclays’ website indicated that its app had begun working again – but that issues persisted with payments and transfers.

Customers replying to Barclays’ announcement about the outage on social media have reacted with fury while reporting a series of problems it is causing them.

One said their card had been declined despite them having funds – another said that that her January wages “had disappeared”.

A family has told the BBC they can’t 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.”

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.

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

Earlier, 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. Today’s 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.

During last July’s major global IT outage, several UK retailers were unable to take card payments and IT services were unable to access payroll after an erroneous update by antivirus company CrowdStrike affected systems worldwide.

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.

Additional reporting by Liv McMahon