He said the economic package was ‘unprecedented in the history of the British state’ and will be ‘one of the most comprehensive in the world’.
The Government will cover 80% of the salary of workers, up to £2,500 a month, under a Coronavirus Retention Scheme. All employers will be eligible and can contact HMRC.
It is expected the first grants will be paid within weeks and the scheme will be up and running before the end of April.
The programme will cover the cost of wages backdated to 1 March and initially run for three months, but will be extended if necessary.
Sunak said the scheme includes everyone who is on a company PAYE system and is designed to cover as broad a range of people as possible.
It comes as the Prime Minister finally ordered all restaurants, pubs and bars to close on Friday (20 March).
The Government is also deferring the next quarter of VAT payments, so there will be nothing to pay from now until the end of June. Businesses will have until the end of the financial year to pay the bills.
Sunak also announced the Coronavirus Business Interruption loan scheme will be available from Monday and will now be interest-free for 12 months instead of six.
Further measures to ensure larger and medium-sized businesses ‘can access the credit they need’ will be announced next week.
Speaking in Downing Street, Sunak appealed to businesses to “please look carefully at support before laying any people off”.
UKHospitality CEO Kate Nicholls welcomed the support package, but urged its swift delivery.
She said: “This generous package will support our fantastic staff, is very welcome and additionally gives hope to those who have been laid off. This may have saved up to one million jobs, but we need it as soon as possible to ensure we can continue to trade.
“While VAT deferrals preserve some cash, we still face rent payments next week before the support is due to arrive. Banks and landlords need to do more to help us bridge the gap towards this generous Government support.
“Damage is being done now, so we need help now.”