The online retailer said the downtime was due to hardware failure.

However, there’s speculation on Twitter and in the national press that Amazon has been attacked by freedom-of-speech campaigners after it stopped hosting WikiLeaks on its servers last week.

Mastercard, PayPal and Visa have all suffered similar attacks in recent days after withdrawing their services to the whistleblowing site.

Online activist group Anonymous, dubbed ’hacktivists’, are alleged to have caused a distributed denial of service (DDoS) attack to shut down Amazon’s website by spamming it with data. However, the group has since tweeted a message denying any connection to the site shutdown.

The group, which tweets under the name AnonOps, said: “We cannot attack Amazon.com. To some journalists: check your sources well please.”

The failure, at around 8pm, affected the etailer’s sites in the UK, France, Germany and Italy, meaning consumers using the site for Christmas shopping were disrupted.

An earlier attempt to hack Amazon last Friday failed.

Freedom-of-speech campaigners have called for consumers to boycott the etailer in the run-up to Christmas.

This story first appeared on marketingweek.co.uk