Kids Company has closed its doors on thousands of young people after running out of money as its high profile founder Camila Batmanghelidjh blamed "rumour-mongering civil servants" and "ill-suited ministers" for the charity's demise.
A Government grant of £3 million was made last week following agreements to restructure the organisation, but some of it was reportedly used to pay salaries to staff, breaking conditions on the gift and prompting moves to reclaim the taxpayers' money.
After the doors closed for the last time, graffiti above the brass Kids Company sign in Bristol read "RIP" with a cross underneath and "THE BEST PLACE THERE WAS" written to one side.
Ms Batmanghelidjh told BBC Radio 4, in an interview to be broadcast in full at 8pm today, the move meant "the doors have to shut" and "we've had to abandon a lot of children".
She called on Prime Minister David Cameron to explain what would now happen to the thousands of vulnerable children helped in 11 street centres and 40 schools.
She said: "That's it, it's the end of Kids Company and actually a bunch of rumour-mongering civil servants, ill-spirited ministers and the media, on the back of a range of rumours, put the nail in this organisation and shut it."
She added: "I have to think: what do I do? There is insolvency law that requires you to behave in a particular way. Therefore, the doors have to shut and there cannot be any service provision - insurance stops, everything stops.
"But I am still left with these kids and their needs. This is devastating - where is the Prime Minister of this country saying what's going to happen to these children?"
Ms Batmanghelidjh said other donors, such as businesses or charitable trusts, had been exhausted or wanted to spend money on specific projects or equipment, leaving the charity unable to cover its running costs.
A Government spokeswoman said: "The Government has supported Kids Company over the last seven years to help it deliver services for vulnerable young people and so we are disappointed it has been unable to move to a sustainable financial position.
"The welfare of these young people continues to be our primary concern and we are now working closely with local authorities to make sure they have access to the services they require."
In a statement, the charity's trustees said its priority was to "secure a future" for the children it had helped after the "sad end" of Ms Batmanghelidjh's organisation, 19 years after it was founded.
The statement said: "It is with the greatest sadness and reluctance that we have reached the decision to close Kids Company. We have been forced to do so because collectively, despite the extraordinary efforts of Camila and her team, some truly enlightened philanthropists and the Government, we have not been able to continue.
"Kids Company has touched and transformed so many young lives and it is a tragedy that this extraordinary work will come to an end leaving many thousands of vulnerable children, young people and families without hope."
In her own statement, Ms Batmanghelidjh added: "I apologise to all the courageous and dignified young people who have touched our hearts and made us brave."
The organisation works with 36,000 children and young people, and officials, charities and councils have been in discussions preparing for the impact the closure could have.
The youth organisation has been hit by allegations of bad financial management, prompting its high-profile founder to quit as chief executive.
Ministers Oliver Letwin and Matthew Hancock agreed to give extra money to help restructure the charity, despite official objections from a Whitehall mandarin who warned they did not think it would offer "value for money".
Kids Company received a £3 million grant from the Cabinet Office last week after agreeing, on the orders of the Government, to make changes in its leadership, management and governance.
But Ms Batmanghelidjh emailed staff within the charity last week to say they would be paid using some of the grant money, according to the BBC.
The BBC reported that the Cabinet Office is making plans to claw back the grant because it believes conditions attached to the use of the money were not met.
Acting Labour leader Harriet Harman, whose constituency of Camberwell and Peckham is served by Kids Company, demanded a plan to ensure the vulnerable youngsters the charity works with are cared for.