I was seven when Nelson Mandela went to prison, by the time he was released, I was 33. But as a student 35 years ago, South Africa was not high on my list of priorities. If ever I gave it a thought, it seemed to be about a brutal struggle between races, where a cruel apartheid regime faced a likely day of destiny with a suppressed black majority goaded to seek succour in extremism and communism.

It was however Mandela who changed this and changed it utterly. Leading by example, his dignity and grace towards his oppressors – and those who were merely silent – were humbling and shaming.  Without training or image advisers, he spoke calmly and without rancour to billions.  And his message was one of justice, reconciliation, forgiveness and unity.  Through it, he succeeded in melting entrenched positions around the world.

It was a truly astonishing achievement and made so many other politicians look hollow. He never really faltered or lost his moral authority.

Nelson Mandela was that rarest of creatures: an indisputably great man. When I join the Mayor in signing the Book of Condolence at South Africa House today it will be one tiny and belated mark of truly heartfelt respect.