Politicians and wartime refugees honour Britain's Schindler Sir Nicholas Winton

Political dignitaries have gathered alongside generations of people saved as a result of the actions of Sir Nicholas Winton to remember and celebrate his life.

Known as "Britain's Schindler", Sir Nicholas, who died last year aged 106, helped 669 mostly Jewish children flee Nazi-occupied Czechoslovakia just before the outbreak of the Second World War.

The London-born stockbroker founded the Kindertransport following a visit to Prague at the end of 1938 during which he felt compelled to help save children there from almost certain death.

His bravery was only made known to the public half a century later, when his family happened upon an old briefcase in the attic containing lists of children and letters from their parents.

Home Secretary Theresa May, MP for Maidenhead, where Sir Nicholas lived, joined Czech and Slovak officials at the Guildhall in London on what would have been Sir Nicholas's 107th birthday.

Survivors from as far as Israel, America and the Czech Republic attended the service alongside descendants of some of those who have since died, to commemorate the life of a man they say they owe their lives to.

Among the rescued "children" to pay tribute was Lord Dubs, who was six years old when his mother put him on one of the eight trains which carried the young people to Britain.

The former Labour MP, who came to consider Sir Nicholas a friend when they met in later life, said he had had the "tenacity and willpower" to take action against the problems facing people in Prague.

He said: "He tackled them with determination and he did it. He could've walked away but he didn't, and to him many of us owe our lives."

Sir Nicholas, known affectionately as Nicky by his family, lived a life full of "love, laughter, passion and commitment", his daughter Barbara said.

Considering the families many of the children went on to have, Sir Nicholas's relatives estimate somewhere in the region of 7,000 people were able to live because of what he did.

Among his many honours were an MBE in 1983 for his services to learning disability charity Mencap, a knighthood in 2003 for services to humanity, and the awarding of a Hero of the Holocaust medal at 10 Downing Street in 2010.

Dame Esther Rantzen, whose That's Life programme in 1988 brought Sir Nicholas's story to public attention, recreated the moment he first met those he had saved.

The clip showing Sir Nicholas in the audience as more and more of those around him stand up after being asked: "Is there anyone in our audience tonight who owes their life to Nicholas Winton?" has been viewed millions of times online.

Addressing those gathered at the memorial service, Dame Esther again asked those who felt they owed their life to Sir Nicholas to stand up.

As dozens of people rose from their seats, she said: "And it was at this stage that Nicky Winton himself turned round and saw for the first time the enormous impact his decision had made not only on one generation but on generations of Winton's children.

"Thank you very much. Nicky, I hope you're watching."

Mrs May, who also addressed those gathered, said she felt privileged to have known Sir Nicholas, whose story she described as "extraordinary".

She recalled speaking to him at an event in 2010, shortly after the Conservatives formed a coalition government with the Liberal Democrats.

Amid laughter from the audience, she said: "He said to me, 'I just want to tell you that coalition means compromise and that isn't always a bad thing. Never forget that'."

The memorial service featured musical contributions including a children's choir who sang from Carl Davis's Last Train to Tomorrow which was written to tell the story of the Kindertransport children.

Sir Nicholas's son Nick said he hoped his father's example would continue to inspire others as they look to the future.

He said: "It is his legacy to inspire and encourage all of us to be actively involved in our own communities. He's inspired me, my sister and many others I know, many of you in this room. And that is one of the ways his memory will live on and stay with us in the future."

A memorial concert, in aid of today's child refugees and featuring actor Rupert Graves and cellist Alexander Baillie, will be held at St John's Smith Square on Friday.