“We’re using the full measure of our fiscal firepower to protect the jobs and livelihoods of the British people,” Sunak will say, according to excerpts of the speech to parliament released by the finance ministry on Tuesday.

“First, we will continue doing whatever it takes to support the British people and businesses through this moment of crisis,” he said in the excerpts.

“Second, once we are on the way to recovery, we will need to begin fixing the public finances – and I want to be honest today about our plans to do that. And, third, in today’s budget we begin the work of building our future economy.”

Britain has suffered the biggest COVID-19 death toll in Europe and the heaviest economic shock among big rich countries, according to the headline measures of official data, after shrinking by 10% last year, its worst slump in three centuries.

Sunak has so far spent almost 300 billion pounds ($419 billion) on emergency support measures and tax cuts.

But Britain has also rushed out Europe’s fastest COVID-19 vaccination programme, raising the prospect of an economic bounce-back once its current, third lockdown is relaxed.

Sunak said in media interviews on Sunday that he would not rush to start addressing Britain’s yawning budget deficit, which is approaching 400 billion pounds - its highest as a share of the economy since World War Two.

Prime Minister Boris Johnson plans to lift lockdown measures gradually, starting with next week’s reopening of schools in England, before most measures are removed by late June.

Sunak is expected to announce an extension of his emergency support measures, including huge income subsidies that are on track to cost more than 100 billion pounds, to provide a bridge for the economy until then.

But he has also said he will “level with people” about how Britain’s 2.1 trillion-pound debt pile would carry on growing without action, which is likely to mean future tax increases.

($1 = 0.7167 pounds)