Nicholas Winton or the 'British Schindler' as he was fondly known for saving hundreds of Jewish children from the Nazis, has died at the age of 106.
Son-in-law Stephen Watson said on wednesday that Winton died peacefully in his sleep at Wexham Hospital in Slough, west of London.
Born in London of German-Jewish parents, Winton travelled to Nazi-occupied Czechoslovakia -- which split into the Czech Republic and Slovakia in 1993 -- as a young employee of the London Stock Exchange.
It was there that he organised trains that transported 669 children, most of them Jews, to Britain in 1939, saving them from concentration camps and near-certain death.
An additional train was set to leave on September 3, 1939, the day Britain declared war on Germany, but the borders were already sealed. None of the 250 children were seen again.
Winton's efforts earned him the nickname "British Schindler" in reference to Oskar Schindler, the German industrialist who rescued hundreds of Polish Jews during the war.
"A good man, Sir Nicholas Winton, has passed away. He will remain forever a symbol of courage, deep humanity and incredible modesty," Czech Prime Minister Bohuslav Sobotka said on Twitter.
President Milos Zeman, who last year presented Winton with the Order of The White Lion, tweeted: "He was a man I admired for his courage."
British Prime Minister David Cameron tweeted: "The world has lost a great man. We must never forget Sir Nicholas Winton's humanity in saving so many children from the Holocaust."
The world has lost a great man. We must never forget Sir Nicholas Winton's humanity in saving so many children from the Holocaust.— David Cameron (@David_Cameron) July 1, 2015
Winton kept quiet about his mission for 50 years until his wife found evidence of it in their attic.
He was knighted in 2003, and his Czech supporters have repeatedly petitioned for him to receive the Nobel Peace Prize.
"He was incredibly unique in that he didn't tell anyone for such a long time" about his wartime activities, said Tomas Kraus, head of the Czech Federation of Jewish Communities.
"He wasn't the only one, there were more such personalities. In his case, it's the modesty that's so unique, he considered it an unimportant episode in his life."
Rabbi Jonathan Sacks praised him as a "giant of moral courage".
"Our sages said that saving a life is like saving a universe. Sir Nicholas saved hundreds of universes," Sacks said, adding: "he will be mourned by Jewish people around the world."
Home Secretary Theresa May, Winton's local MP, called him a "hero of the 20th century".
"Against the odds, he almost single-handedly rescued hundreds of children, mostly Jewish, from the Nazis - an enduring example of the difference that good people can make even in the darkest of times."