David Cameron said "a very, very bright light has gone out" following the death of cancer patient and charity fundraiser Stephen Sutton this morning.
Calling Stephen "deeply inspirational", the Prime Minister said he could "hardly think of anyone I've met with such a zest for life and such a belief that you can get things done, and who wanted to live every minute".
"He was determined not to be cowed by it and to make the most of every single moment on this Earth, and he absolutely did that," Mr Cameron continued.
"I think that's why he created this phenomenon, not just here in the UK, but right around the world".
Deputy Prime Minister Nick Clegg has paid tribute to "selfless" cancer patient Stephen Sutton following the 19 year old's death:
Very sad to hear about the death of Stephen Sutton. Such a brave, selfless and inspirational young man. #stephensstory
Teachers and pupils at Stephen Sutton's former school have paid tribute to the cancer patient, who died this morning aged 19.
Stephen Sutton's former headteacher has paid tribute to the teenager, who he described as "the most exceptional person I have ever known".
Stephen developed a deep understanding of what's important in life. We will miss him enormously but he leaves an amazing legacy and we believe that it is fitting for us to focus our attention on celebrating his life. Stephen is the most exceptional person I have ever known.
Teenager Stephen Sutton, who dedicated his life to spreading happiness and inspiring others, has lost his cancer fight, aged just 19.Read the full story ›
Comedian Jason Manford, who helped to Stephen Sutton with his fundraising for a cancer charity, said the teenager was "the most inspiring person I've ever met".
He said: "Stephen Sutton was the most inspiring person I've ever met and touched more lives than he will ever know.
"He was an incredibly positive young man and a credit to his family, to Burntwood and to humanity itself. The reason we took to him so passionately was because he was better than us, he did something that none of us could even imagine doing.
"In his darkest hour he selflessly dedicated his final moments to raising millions of pounds for teenagers with cancer.
"Some of Stephen's words will stay with me and others forever and they are words to live by - 'life isn't measured in time, it's measured in achievements'.
"If that's true, Stephen, then you had a fulfilling life full of special moments and you will live long in the memory of thousands, if not millions, of people."
Labour leader Ed Miliband has paid tribute to cancer patient Stephen Sutton, who died this morning aged 19.
Tragic news that Stephen Sutton has passed away. His bravery & determination to live life to the full was an inspiration to us all.
Yellow ribbons in support of cancer patient Stephen Sutton, who died this morning aged 19, have been tied on the gates of his former school.
Ribbons have been tied around Chase Terrace Technology College and other parts of Staffordshire.
Stephen's mother announced his death on his Facebook page, where she said her "heart is bursting with pride but breaking with pain for my courageous, selfless, inspirational son".
The Prime Minister has paid tribute to Stephen Sutton, who died this morning from cancer.
I'm deeply saddened to hear that Stephen Sutton has died. His spirit, bravery and fundraising for cancer research were all an inspiration.
Stephen Sutton, who died this morning aged 19, has raised over £3.2 million for charity Teenage Cancer Trust.
The charity said they were "humbled and hugely grateful for what Stephen achieved and continues to achieve for us".
He had originally set out to raise £1 million for the charity.