M&S shoppers hit by service issues after a major cyber incident may be wondering if they should have a back-up way to pay if the usual digital method is unavailable.

The reported cyber attack has affected the retail brand for over a week with online orders still paused, while many customers have been unable to pay using contactless in store.

Amy Knight, personal finance and small business expert at NerdWallet UK, said the service issues are a reminder it’s a good idea to have multiple payment options when you’re out shopping.

She pointed to two good practices: “Many consumers rely solely on mobile or contactless payments, but keeping bank cards handy could save you from the panic of having no way to pay in an emergency.

“Having more than one bank account is also worth considering, as it reduces your dependency on a single provider. It can also be helpful for budgeting to have one card that you use for essentials and another you use for discretionary purchases.”

She said keeping some cash on you is also a good practice, as your area could be affected by IT outages or even power cuts, such as the major blackouts that hit Spain and Portugal recently.

When decided how much cash to have on you, Ms Knight suggested some scenarios to think through:

• If you filled up your car at the petrol station and an IT failure left the card reader out of action, how much would you need to pay for a full tank?
• How much money would you need to feed your family for a day if you couldn’t use card payment or contactless at the supermarket?
• For commuters, how much do you need to cover the cost of getting to work?

Jason Gilmore, tech expert at mobile app design group Adalo, also said it’s important to have a secondary way to pay for items.

He pointed to a good practice: “Rotate through a debit card, a peer-to-peer app such as PayPal or Venmo and some cash so none of them feel unfamiliar when you need them.”

He also said it’s worth saving phone numbers for important services in case there is an issue, such as your bank, your local pharmacy or a taxi firm, depending on your needs.

You can also plan ahead for an emergency with a list of alternative grocery shops or petrol stations. Another tip is to use different devices or profile for your banking versus your everyday online browsing, so you can still operate if malware affects one of your devices.

Scott Dawson, CEO of payment firm DECTA, warned that the M&S incident shows a worrying lack of resilience in the systems used for everyday payments.

He said: “This incident, impacting online services and potentially customer trust, underscores the critical importance of robust digital resilience for businesses, especially those handling transactions and customer data.

“It’s worry that we are seeing the same problem of institutional failure due to lack of reliance in so many organisation that we have become so reliant on.”