Barclays has suffered a major outage, with customers unable to access their accounts using online banking.

Barclays customers in the UK were greeted on Thursday morning with the message: "5 - Sorry - Barclays Online Banking is currently unavailable".

A spokesperson for the bank, which has over 24 million customers, told The Independent: "We're currently experiencing some technical problems – customers are still able to use Barclays Mobile Banking app to check their balance, make and receive payments. We’re on it, and as soon as it’s fixed we’ll let you know."

Issues with Barclays online and telephone banking began at around 10 am on Thursday, 20 September

The banking giant has been responding to concerned customers on social media, acknowledging the issue and saying that it hopes to get its systems back up and running soon.

"Hey Zebre, we're experiencing some issues at the moment :( We're hoping to be back up and running very soon so that you can pay your rent," a member of the bank's social media team tweeted in response to a customer complaint.

A statement published to Twitter advised customers to use the mobile app to access their accounts.

"If you're unable to access Online Banking, Telephone Banking, or use some features in our app, we're sorry," the statement read.

"You can still make payments and check your balance in our Mobile Banking app as normal. We're looking into the problem now, and we'll update you here as soon as possible. Thanks for bearing with us."

The bank's website noted issues with online banking, telephone banking and branches.

"We're sorry, you won't be able to speak to us right now – we're working to fix a problem with this service," a status update for its telephone banking service read.

"You can still use our automated Telephone Banking service to manage your account."

Barclays advised customers to keep up-to-date through its online status page.

Money expert Tashema Jackson, who works at uSwitch.com, took the opportunity to advice Barclays' customers on what action they can take in the event of a major outage.

"If you think you’re facing a loss due to an unexpected online banking failure you can lodge a complaint with your bank for any financial damages incurred as a result of the disruption," Ms Jackson wrote in an email to The Independent.