A German author has claimed that Adolf Hitler was so drug addled that his veins were ruined by injections and that he "did not spend a day sober" after an attempt was made on his life in 1944.

Norman Ohler has revealed that the Fuhrer allegedly became so addicted to the heroin-like Eukodel, he turned into a 'super junkie' whose drugs fuelled his paranoia and erratic behaviour in a forthcoming book.

Ohler's book Blitzed: Drugs in Nazi Germany, which is released on 6 October, refers to diary entries written by Hitler's personal physician Theo Morell.

One entry by Morell reads: "I cancelled injections today, to give the previous puncture holes a chance to heal.

"Left inside elbow good, right still has red dots (but not pustules), where injections were given," the diary reads.

According to the author, Hitler started using drugs after he survived an assassination attempt by German resistance, known as Operation Valkyrie, which reportedly left him with severe mental health issues.

Ohler told the Telegraph: "I'm afraid that from 1944 onwards, Hitler did not spend a single day sober. Before then, he was a very public person... but the attempt on his life left him withdrawn, paranoid and anxious."

His book also outlines how the meth-like substance called Pervitin was prevalent among Nazi soldiers. Ohler told the BBC: "The German army was trying to win the battle against sleep.

"That's why they used it and in the beginning it worked wonders in the attack on Poland and in the so-called Blitzkrieg."

British war historian, Antony Beevor, said Ohler's book's findings explained Hitler's irrational military tactics during the Battle of the Bulge, in which the dictator tried in a desperate last attempt to defeat the allies.

"All of these elements show how he was really no longer in control of himself, but he was still in control of the German armies," Beevor told the BBC's Today programme.