Amazon has come under intense scrutiny after the revelation that it sells numerous books supporting Holocaust denial.

The publishing giant was found to have made available a large number of titles by authors arguing why they believe the Holocaust did not happen. Some are even allocated an option of speedy delivery for Amazon Prime customers.

One book, The Six Million: Fact or Fiction?, in reference to the figure of six million Jews who died during the Holocaust, is being sold in paperback for £7.95 and has received five-star ratings from 44 Amazon users.

Other titles available on the site include The Myth of Extermination of the Jews by Carlo Mattogno, Holocaust: The Greatest Lie Ever Told by Eleanor Wittakers, and The Hoax Of The 20th Century: The Case Against The Presumed Extermination Of European Jewry by Arthur R Butz.

Twitter users voiced their anger at Amazon, with one account describing the tech company as "desperate", another calling it "shameful".

Holocaust denial is not illegal in the UK, meaning said books are still available on Amazon's UK store. But it does carry a prison sentence in Germany and France, where some titles were being sold via the website before being taken down following an investigation by the Sunday Times.

A spokesman from Amazon UK declined to comment further after being contacted by IBTimes UK.

Karen Pollock, the chief executive of the Holocaust Educational Trust, believes Amazon's decisions to sell the books online is "shocking" and "wrong".

"The Holocaust was one of the most well documented and researched periods in history, yet even in 2017, over 70 years later, there are still those who deliberately deny, denigrate and belittle the memory of the Holocaust," she said. "Holocaust denial is highly offensive and the intent is anti-Semitism, pure and simple. To have this offensive material widely accessible via any retailer is shocking and wrong."

The story comes at the same time as the release of the film Denial starring Rachel Weisz as Deborah Lipstadt, a Jewish author who is sued for libel by Holocaust denier David Irving, played by Timothy Spall, for depicting him as a denier. Lipstadt had to prove Irving was lying about the Holocaust taking place. Irving lost the case.