She was a humble heroine from a different era – one who would have poured scorn on the notion of seeking fame or plaudits for her work.

And perhaps that's why the extraordinary tale of Norwich missionary Elsie Tilney took 70 years to come to light.

But now the unassuming spinster who risked her own life to protect Jewish people from the horrors of the Holocaust will be forever remembered in her home city, following an emotionally-charged service at her spiritual home.

Relatives, civic dignitaries, and representatives from the Jewish community gathered at the Surrey Chapel on Botolph Street to pay tribute to Elsie, and to celebrate her bravery and compassion during the darkest days of the Second World War.

Guests included Ruth Sands, who was rescued by Elsie from Nazi-annexed Austria and taken to Paris as a baby in 1939, and her son, London barrister Prof Philippe Sands, whose research in recent years has resulted in Elsie gaining international recognition.

In January, she was formally honoured as Righteous Among the Nations by the official Holocaust remembrance authority at Yad Vashem in Israel – only the 21st British recipient of the honour.

Her medal was accepted by her closest living relative, 84-year-old Joseph Schultz, who lives in Bishopgate, Norwich, and was among those who attended Surrey Chapel last night for the special service and the unveiling of a permanent display board by Sheriff of Norwich, William Armstrong.

Mr Schultz, whose mother was Elsie's cousin, said: 'It makes me very proud to have such a distinguished ancestor. I feel a bit overwhelmed. I was very proud, obviously, but I am only the custodian of it. It is Elsie's medal, not mine.

'Nobody knew about these stories because she didn't swank around telling people about it. She was a very reserved type of person, a very Christian lady, and she must have been a very, very brave woman indeed to live under these conditions in France.

'I think now it will be forever in the memory of the people of Norwich and Norfolk. There will be no way people can forget about it now, because there will be a permanent record here in the chapel.'

Elsie was described as a 'formidable English spinster' – devout, devoted and, by some accounts, quite over-bearing.

But Prof Sands said it was her compassion that set her apart from so many others.

He said: 'The crucial point is that to be recognised by Yad Vashem as a righteous person, you have to prove that the person risked their life to save another. To save someone's life is an incredible thing, but to risk your life to save someone you do not know is very special.

'One of the things I have asked myself is what really motivated her? She was motivated by something that went beyond ideology or pure religious belief. An abstract principle is not enough to be heroic – she was motivated by a very deep human compassion.'

The Israeli Embassy was represented at the event by director of public diplomacy Rony Yedidia-Clein, who said: 'People like Elsie didn't talk about what they had done, but there are so many stories that still keep coming up. We thought half a generation ago that we would know all these stories, but Yad Vashem keeps uncovering them and recognising people who have done so much to save others. I think Norwich and Norfolk have a lot to be proud of, that a daughter of this place was able to stand up for what she believed in and do what she had to do.'

Surrey Chapel pastor Tom Chapman added: 'We are celebrating not only Elsie's life and example but, more significantly, what she stood for. She would not have sought glory or recognition for herself, but she was inspired by her faith to do great things. The world is not made of grand heroes, but of ordinary heroes who stand up and do the right thing when it really counts.'

The story of Elsie Tilney may not have ever come to light if not for the discovery of a yellowing scrap of paper in a London attic.

Prof Philippe Sands was determined to discover how his mother Ruth had got from Vienna to Paris in 1939 before she was a year old.

Five years ago, following the death of his father, he opened an old suitcase belonging to Mrs Sands and out fell a handwritten note which reads: 'Miss E. M. Tilney, 'Menuka', Blue Bell Rd, Norwich, Angleterre.'

This was the first time he was aware of Elsie's role in saving his mother.

As a barristers and a litigator, he said he was well practised in piecing together cases from limited information, so he embarked on a 'complex detective story' which eventually led him to the Surrey Chapel and its archivist Rosamunde Codling, who helped him piece together the story.

He is writing a book about his findings, which he expects to publish next year.

Mrs Sands, now aged 76, said: 'This has all happened through Philippe's hard work – and between you and me I think he was irritated by his mother's ignorance. The only thing I knew was that my father always said I was smuggled out of Vienna to Paris by an English woman, but that's all we knew. Then we found this scrap of paper with Elsie Tilney's name on it in my father's papers.'