"Last week, the British people voted for change. And over the past 72 hours I have begun the work necessary to deliver on that mandate," she will say in a speech to business leaders, according to excerpts released by her Treasury department.

"Where governments have been unwilling to take the difficult decisions to deliver growth – or have waited too long to act – I will deliver."

Reeves, Britain's first female finance minister, needs to improve growth to help finance increased spending on public services without raising the main taxes paid by working people.

She has already ruled out higher borrowing for day-to-day spending and has said that debt must be falling as a share of the economy by the fifth year of any forecast.

The task has not been made any easier by the new government's inheritance from the Conservatives.

Living standards have stagnated since 2010, public debt is at almost 100% of gross domestic product (GDP) and tax as a share of GDP is on track to rise to the highest level since just after World War Two.

In the speech Reeves will outline the first steps the new government will take to fix the foundations of the economy, according to the Treasury. Newly elected Prime Minister Keir Starmer has already pledged to use his massive parliamentary majority to rebuild the country.