Ocado has apologised to customers and promised compensation after it was forced it to cancel thousands of deliveries due to a systems outage.

The online grocer said an “operational failure” caused it to cancel customer orders yesterday. It has since fixed the problem and service has “returned to normal”.

An Ocado spokeswoman said: “An operational issue at our warehouse has caused us to cancel a number of orders.

“All customers whose order has been cancelled will have, or will soon receive, a phone call from Ocado customer service at which point they will be able to re-schedule their order.”

She added: “We apologise for any inconvenience this has caused.”

Customers will receive refunds and compensation where appropriate, although the details have not been decided.

The move comes after analysts at Barclays re-iterated fears that the company could breach its banking covenants after ploughing £200m into its new distribution centre in Dordon, Warwickshire, due to open next year.