The Holocaust did not start with the gas chambers. Anti-Semitism did not start with Hitler. This most pernicious hatred has reared its head time and time again throughout history, sometimes changing shape, but never really going away.

In the late 19th and early 20th centuries, one way that this hatred manifested itself was in what is now known as the Dreyfus Affair. Alfred Dreyfus, a Jewish captain in the French army, was falsely accused of passing military secrets to Germany. He was arrested, found guilty of treason, and sentenced to life imprisonment on Devil’s Island, a penal colony off the coast of French Guiana. He was innocent. This happened simply because he was Jewish.

After being convicted in 1894, Dreyfus was paraded through the streets of Paris. His insignia were torn from his uniform, his sword was broken. The crowds shouted “death to the Jews” as he was dragged through the streets.

When, a couple of years later, the head of the army’s intelligence unit suggested that Dreyfus was innocent, his bosses went to extreme lengths to conceal the evidence. Eventually, the actual perpetrator, Major Ferdinand Esterhazy, was tried and acquitted for the crimes, prompting Emile Zola to write his now-famous “J’accuse” letter in 1898, accusing the military of a cover-up and decrying the anti-Semitism that allowed Dreyfus to be treated so appallingly.

The way that a proud Frenchman was degraded and imprisoned still resonates today. In times of trouble, Dreyfus was seen as a Jew first, a Frenchman second. And as a Jew, he was hated and decried.

John McDonnell yesterday called the Julian Assange trial the “Dreyfus case of our age” after a two-hour visit to the WikiLeaks founder. How wrong could he be?

Assange is wanted in the US for a string of alleged crimes. He spent seven years hiding in the Ecuadorian embassy in London to avoid extradition to Sweden over allegations of sexual assault. He is not the subject of an anti-Semitic witch hunt. Unlike the horrors that Dreyfus faced, Assange is subject to the rule of law. Assange’s loyalty – his very nationality – is not up for question or challenge, unlike Dreyfus whose very Frenchness was deemed incompatible with his Jewish identity.

McDonnell went on to claim that there were parallels between the two due to “the way in which a person is being persecuted for political reasons”. To be clear – Dreyfus was not persecuted for “political” reasons. He was persecuted for being a Jew.

For Jewish people today, the name Dreyfus is synonymous with centuries of anti-Semitic persecution which took place in Europe and still persists today. It warns us that no matter what Jews give to their state, however patriotically, and no matter what contributions we are recognised for, we are always the “other”, and our loyalties are never above question.

Assange is no parallel to Dreyfus. For the shadow chancellor to suggest that they are facing the same battles is not only absurd but profoundly offensive. It downplays the institutionalised anti-Semitism, hatred and degradation that embodies what happened to Dreyfus and is particularly ludicrous when Assange himself has perpetuated anti-Semitic conspiracy theories.

For a man presiding over a party being investigated by the Equalities and Human Rights Commission for anti-Semitism to make such a claim is on the one hand extraordinary and, on the other, unsurprising. For John McDonnell to proclaim that Julian Assange is the Dreyfus of our times is a deliberate distortion of history and a gross misrepresentation. But then, surely, he understands that?

Karen Pollock is chief executive of the Holocaust Educational Trust