The government has placed the economy on a wartime footing to support businesses and people affected by coronavirus, announcing state-backed loans of at least £330bn as the outbreak escalates.

The chancellor, Rishi Sunak, said if more help was needed it would be provided, with a pledge to deliver “whatever it takes” to keep companies and households solvent.

Saying the British state would need to intervene in the economy in ways that were unimaginable just weeks ago, the chancellor said he would also provide tax breaks and other measures worth £20bn to protect companies and households suffering amid the economic collapse triggered by the virus.

Cash grants worth £25,000 would be made to retail, leisure and hospitality firms to help them survive the period of turbulence. The smallest businesses in the country across all sectors of the economy will be able to seek grants worth £10,000.

Business rates – taxes paid on commercial properties – will be scrapped this year for all companies in the retail, leisure and hospitality sectors. “Every single shop, pub, theatre, music venue, restaurant … will pay no business rates for 12 months,”Sunak said.

Speaking alongside the chancellor and the government’s chief scientific adviser, Sir Patrick Vallance, Boris Johnson said: “We must act like any wartime government and do whatever it takes to support our economy.”

Calling the scale of the challenge unprecedented since the second world war he added: “Yes, this enemy can be deadly, but it is also beatable.”

The government intervention comes after it faced intense criticism accusing it of putting the survival of pubs, clubs, theatres and other UK venues in doubt after advising the public to stay away over the coming weeks. Observers had said struggling firms wouldn’t be able to claim on their insurance, as the announcement was only advisory.

However, Sunak said firms with insurance would be able to claim on pandemic insurance policies, if they had them, but that he had outlined the further steps to support companies in the worst-hit sectors of the economy.

“This is a comprehensive, coordinated and coherent response to what is a serious and evolving economic situation. These are only the first steps,” he added.

Other nations around the world are stepping up their efforts to combat the unfolding economic collapse amid the coronavirus outbreak. Donald Trump’s administration announced earlier on Tuesday that it planed to send cheques directly to American citizens as part of a package of emergency financial support to the world’s largest economy worth at least $850bn (£702.1bn).

He said he would set out further steps in the coming days and that he was holding talks with unions and business groups to develop a form of employment support to help protect jobs and incomes.

Sunak and Johnson were vague about the specific help that would be provided to individuals in difficulty because of the virus, beyond a three-month mortgage holiday and the promise of more details to come.

However, the amounts involved are unprecedented in peacetime. The sum of £330bn is equivalent to 15% of GDP, and Sunak said more would be provided if needed.

The loans, made on “attractive” but unspecified terms, would allow firms to carry out fundamental day-to-day tasks such as paying wages and rent bills and buying stock. The money, available from the start of next week, will be offered via the Bank of England for bigger firms, while smaller enterprises can seek business interruption loans of up to £5m each.

Emergency legislation being presented by the government on Thursday to coordinate the response to coronavirus will include the power “to offer whatever further financial support I decide is necessary”, Sunak said.

The announcements came as No 10 created a new system of ministerial committees devoted to streamlining the government response to the virus.

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Johnson will still chair regular meetings of the existing Cobra emergencies committee, but also another, coronavirus-specific committee of ministers and senior officials, known as C-19, which will meet daily.

Additionally, No 10 has created four so-called implementation committees focusing on health, the economy, preparedness elsewhere in the public sector and on the international response, all of which will feed into C-19.

The health committee will be chaired by Matt Hancock, the health secretary; that on the economy by Rishi Sunak; the public sector committee by Michael Gove; and the foreign secretary, Dominic Raab, will chair the international committee. All will attend the C-19 meetings.