Charities will get a £750 million coronavirus bailout package, Chancellor Rishi Sunak has announced.
The government say the package of support will ensure they can continue their vital work during the coronavirus outbreak.
And the government will match donations made to the BBC's "big night in" fundraiser later this month - pledging to donate a minimum of £20 million.
It comes after charity chiefs warned the sector faced a £4 billion funding black hole in the wake of the Covid-19 outbreak leaving vital organisations helping to fight the virus months away from running out of cash.
But Mr Sunak said: "The truth is we will not be able to match every pound of funding they would have received this year."
Some £360 million will be directly allocated by Government departments to charities providing key services and supporting vulnerable people during the crisis - including hospices taking pressure off the NHS.
A further £370 million for small and medium-sized charities, including through a grant to the National Lottery Community Fund for those in England, will support organisations "at the heart of local communities which are making a big difference during the outbreak, including those delivering food, essential medicines and providing financial advice."
Voluntary sector leaders said their cashflow crisis is 100 times worse than it was during the financial crash of 2008, because "our income has literally stopped overnight."
St John Ambulance, which is now solely focused on supporting the NHS in fighting coronavirus - only has enough cash to keep operating until August.
More than 750 volunteers from the organisation have offered to help staff the new NHS Nightingale hospital set up in London's Excel centre to treat Covid-19.
The situation is drastically worse than it was after the financial crash of 2008 - when the government arranged a £40 million bailout for the voluntary sector.
Announcing the package Chancellor Rishi Sunak said: “Our charities are playing a crucial role in the national fight against coronavirus, supporting those who are most in need.
“It’s right we do everything we can to help the sector during this difficult time, which is why we have announced this unprecedented £750 million package of extra funding.
“This will ensure our key charities can continue to deliver the services that millions of people up and down the country rely on.”
Karl Wilding, chief executive of the National Council for Voluntary Organisations (NCVO), which represents charities, said: "With charity shops shut and fundraising events cancelled, we estimate charities stand to lose around £4bn in 12 weeks as a result of the crisis. We have been pushing for government support because we know how many people and communities rely on the services charities provide, many of which are now at risk."
He added: "Today’s announcement is an important first step, though it will not be enough to prevent good charities around the country from closing their doors. Even many that survive will look very different in a few months’ time, with a severely reduced capacity to provide the support that people rely on.
"At a time of crisis, charities want and need to be able to give their all to supporting people who need it most. They cannot do that if they have to suspend their work or close altogether. We know this is not something that the government wishes to see any more than we do, so we will continue to push for the support needed so that charities can keep serving the public. We would welcome a commitment from the government to review the level of this support as the crisis continues."
Barnardo's Chief Executive Javed Khan welcomed the funding - but said it was a "sticking plaster" which doesn't go far enough.
He said: "Demand for our services is already skyrocketing with more children experiencing domestic abuse, and at greater risk of sexual abuse at home and online. Mental health is moving from crisis to catastrophe and more families are falling into poverty
“Financially, the worst is yet to come as the economic downturn continues and I urge ministers to keep the package under review.
“Now more than ever we need the great British public to support charities across the sector – responding to emergency appeals like Barnardo’s Coronavirus Crisis appeal to ensure we can continue to support the most vulnerable in their hour of need.”
Nick Moberly, chief exec of the MS Society called for more detail on how the cash would be distributed.
He said: "We urgently need detail on whether charities who support disabled people are eligible for support – and how the money will be allocated.
“More than 130,000 people live with MS in the UK, and they are relying on us now more than ever. Demand for our services has soared during this pandemic and we’re doing all we can to be there for everyone in the community, many of whom are extremely vulnerable.
“It’s vitally important people with MS are protected during this crisis and we’ll be seeking reassurance that charities like ours won’t be forgotten.”
Health Secretary Matt Hancock said: “The entire charity sector has stepped up as part of our national effort to tackle coronavirus – from helping our NHS heroes to ensuring the most vulnerable among us are cared for properly.
“Hospices have suffered a huge challenge to their funding due to the outbreak of coronavirus but at the same time continued to play a vital role in delivering compassionate, quality end-of-life care for many people. I am delighted that this cash boost will provide further financial stability and support them to increase capacity of NHS Services and provide stability as we manage our response to coronavirus.
“It’s vitally important we all continue to support our fantastic and hardworking hospices and their staff during this unprecedented time, and the whole country is grateful for the incredible work they do.”
Mr Wilding told a committee of MPs last week that the charitable sector was predicted to raise £12.5 billion in the next quarter.
Instead, organisations are expected lose £4 billion - with many unable to cut costs by sending staff home because they are delivering vital public services, such as staffing hospices to take pressure off the NHS.
Mr Wilding said: "Mothballing staff when demand is increasing is the opposite of what you want to do."
He said organisations face losing most or all of their normal income because fundraising events have been cancelled and charity shops have been forced to close.
Martin Houghton-Brown, Chief Executive of St John Ambulance gave a stark warning that his organisation faced tough decisions and an uncertain future.
He told the committee: “Our entire organisation is now delivering for Covid-19. And quite frankly if the support doesn't come we will run out of money.”
If the charity run out of money, he said, trustees would have to make “very difficult judgements about the future of St John Ambulance.”
