“Our experienced team – supported by leading cyber experts – is working extremely hard to restart online and app shopping.

“We are incredibly grateful to our customers, colleagues and partners for their understanding and support.”

It said its stores remain open despite the issues affecting online ordering.

Previously, the firm was dealing with problems which affected people using Click & Collect, as well as paying with gift cards.

Since it suspended online ordering, M&S has responded to social media posts advising customers that these problems persist.

“Gift cards, e-gift cards and credit receipts can’t currently be used as a payment method in store or online,” it said in response to one person on X.

But it told another that if people have already received an email telling them an item is ready to be collected, they should be able to go into the store and pick it up.

“We’re holding all parcels in store until further notice, so there’s no risk of it being sent back,” it said.

But some people have criticised the firm for its handling of the outage, particularly around its messaging to customers.

“After being told yesterday in the evening the problem with gift cards was sorted, went in store today and was sent away again,” one person told the firm in a post on X.

They said it was the fourth day in a row they had tried and failed to use their M&S gift card.

Meanwhile despite the frustrations, some people online have praised in-store staff over their service amid the problems, and called for customers not to take their frustrations out on workers.

But many still appear to have questions over how existing purchases, orders and returns will be impacted by the continued fallout from the cyber attack.

A spokesperson from the Information Commissioner’s Office told the BBC M&S it was “assessing the information provided” after M&S told it about the incident.

The firm previously said on Tuesday it had reported the incident to the National Cyber Security Centre (NCSC), and the National Crime Agency told the BBC it was working with the NCSC to support the firm.

M&S is the latest major name to experience significant disruption to its online services in recent months.

Morrisons faced huge problems with its Christmas orders last year, with deliveries cancelled and discounts not applied.

This was followed by two major banking outages on what was pay day for many in the first two months of this year.

In January, serious IT problems at Barclays affected the bank’s app and online banking. It was later disclosed Barclays could face compensation payments of £12.5m.

In February, several banks – notably Lloyds – faced outages, leaving businesses unable to pay staff.