Gordon Brown has praised the “brave and courageous” 91-year-old Denis Avey, who swapped places with a Jewish prisoner at Auschwitz, as he marked Holocaust Memorial Day.

Mr Avey, along with Holocaust survivor Ben Helfgott and members of the Holocaust Educational Trust, visited Downing Street today as part of the lead-up to HMD on Wednesday.

Mr Brown, watched by his wife Sarah, signed the Holocaust memorial book and spoke to the group, which also included two non-Jewish sixth-form pupils who visited Auschwitz last year, for 45 minutes.

In 1944, Mr Avey was a prisoner of war held in Monowitz, one of the smaller camps alongside Auschwitz, and after hearing rumours about the neighbouring camp he convinced an unknown prisoner to swap uniform and places for two nights so he could witness the atrocities for himself.

Whilst in the camp he befriended Jewish prisoner Ernst Lobethall.

He gave Mr Lobethall 200 cigarettes, used as “currency” for bribing guards, which helped save his life.

Mr Lobethall died in 2002 but had recorded his story, about the prisoner known to him as “Ginger” for the US-based Shoah Foundation, without ever meeting his saviour.

Addressing Mr Avey directly, Mr Brown said: “It is a huge honour to meet you. We are very proud of you. We’re very grateful you are here, not just because of your courage but your willingness to tell people what happened, so the world does not forget.”