Fifteen also formed part of the Fifteen Foundation, which aimed to inspire disadvantaged youth, including those with drug or alcohol problems, the unemployed and the homeless, to believe in themselves and the possibility of becoming chefs.
Speaking about Fifteen during an appearance on 'The Graham Norton Show', Jamie added: "It was 13 years of hard work and Fifteen was my baby, but I ran out of money, ran out of everything and it was really tough, but you have to crack on and try to get yourself together. I've had the best of it - I don't know anyone who had it better than me - and I've had the worst of it - that's life. You have to focus it to a positive."
Last year, Jamie spoke about needing to pump £12.7 million ($25.5 million) of his own savings into his Jamie's Italian restaurant chain to save it from collapsing, although the chain eventually went into administration this year.
He explained: "We had simply run out of cash, and we hadn't expected it. That is just not normal, in any business. You have quarterly meetings. You do board meetings. People supposed to manage that stuff should manage that stuff.
"I had two hours to put money in and save it or the whole thing would go to s**t that day or the next day. It was as bad as that and as dramatic as that."