Jamie Oliver was forced to pump £12.7 million of his own savings into his Jamie's Italian restaurant chain to save it from collapsing.

The 43-year-old celebrity chef has opened up about the ''dramatic'' incident last September in which his chain of Italian restaurants - which he first opened in Oxford in 2008 - unexpectedly ''ran out of cash'', forcing him to use his own money to revive the failing business.

He said: ''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.''

The 'Jamie's Kitchen' star - who is worth an estimated £150 million - made an emergency cash injection of £7.5 million at first to keep the business afloat, before adding another £5.2 million over the following months.

Jamie admits he still isn't sure what caused the sudden financial decline of the chain, but says wage increases, higher rent costs, and Brexit - the decision for Britain to leave the European Union (EU) - were contributing factors.

Speaking to the Financial Times newspaper, he added: ''I honestly don't know [what happened]. We're still trying to work it out, but I think that the senior management we had in place were trying to manage what they would call the perfect storm - rents, rates, the high street declining, food costs, Brexit, increase in the minimum wage. There was a lot going on.''

The financial meltdown of Jamie's Italian caused the television star to shut down 12 of the 37 UK restaurants he had opened, including three in London.

Jamie has also since closed his ''British pizza'' brand Union Jacks, as well as his Recipease deli and cookery school.