In the latest of our guest blogs for Holocaust Memorial Day, Martin Docherty, MP for West Dunbartonshire, considers the significance of the experiences of some of the lesser known victims of Nazi persecution and murder.

Every January as we mark Holocaust Memorial Day, the importance of the event is always illustrated by the stories of new crimes against humanity we had not previously been aware of.

A date chosen specifically to mark the liberation of Auschwitz-Birkenau, and the symbolism that camp had in the killing of six million Jews by the Nazi regime, it nonetheless allows us to reflect upon the circumstances which allowed this, and other such atrocities, to take place.

One example which is of particular interest to me, and which Holocaust Memorial Day also gives us the chance to commemorate, are the crimes committed against both the disabled and LGBT community under the National Socialist regime.

These groups, which were considered to be a threat to Aryan genetic purity, and to be unable to contribute to the society being built in Nazi Germany –  evidence there from the very beginning of the regime that they would remorselessly seek to exploit the weakest and most vulnerable in society in order to propagate a perverted ideology.

It was perverse because it required the cooperation of medical professionals in selecting those with physical or mental disabilities, conducting cruel and debasing experiments on them; deciding whether they would be executed, and often supervising these legalised killings – inverting the very principles of a caring profession and exposing the depravity of Nazism.

This T4 programme became a model for the killings of other, mainly ethnic or national groups, and facilities like Hartheim Castle became among the first places to practice the forms of mass killing which would define the Holocaust. It also provided an indisputable example of the way in which discrimination and hatred of diverse groups will inevitably grow and precipitate a slide into true depravity.

As a gay man, and with a younger brother who died aged 15 because of complications linked to his physical disabilities, these often overlooked mass killings strike close to home. My brother, Graham David Docherty, was both quadriplegic and unable to express himself verbally but with the help and care of family, friends and carers he was able to lead a life which had real purpose and brought real happiness to us all.

The diversity of humanity is its strength – there is no single way of being human, and each of us draws strength from each other’s humanity. The crimes of the Holocaust were so great because they targeted a group which was itself so diverse, and also because it was the apex of a perverted ideology which we must never allow to reappear.

As we begin to fully understand the global rise of a new, less empathetic, less kind politics, we must be constantly vigilant of how intolerance of one group will almost certainly lead to intolerance of others. This Holocaust Memorial Day, let’s remember and try to understand all of the crimes of the 20th Century, and do our best to make sure they are never repeated.