The government has acknowledged the UK is already in a recession as its independent forecaster predicted that the economy would shrink further next year.
The Office for Budget Responsibility (OBR) says higher energy prices driven by the war in Ukraine are largely to blame for the downturn.
It also believes the country will not start growing again until 2024.
It comes as the chancellor lays out his plans to get the economy back on track.
Delivering his Autumn Statement to Parliament, Jeremy Hunt said "families, pensioners, businesses, teachers, nurses and many others are worried about the future".
But he said the OBR believed his plan would lead to a "shallower downturn" with fewer jobs lost.
The OBR says the war in Ukraine had taken the wind out of the global economic recovery from the pandemic, forcing already indebted governments to borrow more to support people with their energy bills.
In the UK, it said the rising prices were eating into people's wages and dragging on the economy.
Autumn Statement 2022: Key points at-a-glanceWhat is the OBR and why does it matter?
The OBR says that overall this year, the economy is still forecast to grow by 4.2%.
But it said it would shrink by 1.4% next year, before rising by 1.3%, 2.6%, and 2.7% in the following three years.
A recession is defined as when a country's economy shrinks for two three-month periods - or quarters - in a row.
Typically during a recession, companies make less money, pay falls and unemployment rises. This means the government receives less money in tax to use on public services.
'Shallower recession'
"The [OBR] judge that the UK, like other countries, is now in recession," Mr Hunt told MPs. "It says higher energy prices explain the majority of the downward revision in cumulative growth since March."
But he added: "The OBR confirm that because of our plans, the recession is shallower, and inflation is reduced. Unemployment is also lower with about 70,000 jobs protected as a result of our decisions today."
Why does the government want to cut spending?
Mr Hunt hopes his Autumn Statement - which lays out £55bn of tax rises and spending cuts - will help restore credibility in the eye of international investors.
It comes after former Chancellor Kwasi Kwarteng promised major tax cuts without explaining how they would be paid for in his controversial September "mini-Budget".
This caused the pound to fall to a record low and drove up government borrowing costs to unsustainable levels, forcing the Bank of England to step in to calm markets.
Part of the problem was that Mr Kwarteng declined to publish an independent OBR assessment of his plans, as would normally be the case.
Mr Hunt, who has now scrapped most of his predecessor's plans, said the cost of government borrowing had since fallen and the pound had strengthened.
He added that the "lower interest rates generated by the government's actions are already benefitting our economy and public finances".