Amazon and Marks & Spencer’s websites were taken offline on Sunday night during the key Christmas trading period amid ongoing cyber threats by pro-Wikileaks saboteurs Anonymous.

Amazon’s sites in the UK, Austria, France, Germany and Italy, and that of M&S, which is on a platform provided by the etail giant, were down for about 30 minutes.

Despite the outage occurring in the wake of online activist group Anonymous’s threats to attack Amazon, the etailer insisted the incident was unrelated.

“The brief interruption to our European retail sites last night was due to hardware failure in our European data centre network and not the result of a DDoS (distributed denial-of-service) attempt,” said an Amazon spokesman.

Despite Amazon’s declaration, a message posted on a Twitter account thought to be affiliated to Anonymous, suggested an attack had been launched. It said: “We can’t confirm anything because we’ll lose our accounts again. Be alert and you will realise.”

Anonymous targeted Amazon following the etailer’s withdrawal of hosting for the whistle blower website. The so-called ‘hacktivists’ earlier attempted to sabotage Amazon’s site last week but publicly announced it had failed because it did not have sufficient “forces” to penetrate the etailer’s defences.

The hacktivists also said afterwards: “After the attack was so advertised in the media, we felt that it would affect people in a negative way and make them feel threatened by Anonymous. Simply put, attacking a major online retailer when people are buying presents for their loved ones, would be in bad taste.”

Anonymous interrupted the operations of MasterCard’s website last week after the payment firm refused to process donations to WikiLeaks. Paypal was also targeted and reportedly experienced an outage. The payment processing firm has since decided to allow donations to go through to WikiLeaks.

Amazon said that all its servers are back up and running and normal service has been resumed. M&S said it did not expect any further disruption to customers.

For further insight see this week’s Need to know