The latest YouGov poll, produced for The Times newspaper, shows the Labour Party has taken a 17-point lead over the Conservatives.
The poll comes off the back of the government's mini-budget and the decision to drop the top rate of tax, which had been 45 per cent for those earning over £150,000 a year.
Many political commentators have expressed their concerns over the announcement from Chancellor Kwasi Kwarteng, with the pound dropping to record levels last week.
This new poll suggests the general public are also losing confidence, with Labour now opening up the biggest lead since YouGov polls started in 2001.
This news comes just three weeks after Liz Truss was appointed Prime Minister and the PM is 13/8 to retain her role after the next election.
A Labour Majority at the next General Election is now available at 2/1, with a Conservative Majority 10/3 and a Conservative Minority currently 12/5.
The latest figures show that 72 per cent of voters polled - including 69 per cent of those that voted Conservative in the last election - were opposed to the tax decision by the Chancellor.
The poll also shows just nine per cent of voters quizzed thought the budget would benefit them and only 15 per cent believed the decision would boost the UK's economy.
Having been carried out last weekend, the YouGov survey highlighted a big drop in support for the government, decreasing by four percentage points to 28 per cent.
In contrast, Labour's backing has gone up by five percentage points, lifting to 45 per cent, a number the party has not held since Tony Blair's time as leader.
The poll figures were released on the day that Labour chief Sir Keir Starmer makes his keynote speech at the party conference in Liverpool.
After 12 years of Conservative leadership, Starmer, 4/6 to be Prime Minister after the next election, is expected to state that Labour has "changed" and that the UK can be a "growth superpower".
There has already been a reaction from the Conservatives following the YouGov poll results, with Huw Merriman - the MP for Bexhill and Battle in East Sussex – one of the first to respond.
Merriman stated: "Those of us who backed Rishi Sunak lost the contest but this poll suggests that the victor is losing our voters with policies we warned against.
"For the good of our country, and the livelihoods of everyone in our country, I still hope to be proven wrong."
Meanwhile, the Bank of England has revealed that they will 'not hesitate' to increase interest rates, should the pound continue to drop.
Sterling fell to a record low against the US dollar earlier this week, to $1.03, although it did rise by over one per cent in the Asia currency market on Tuesday.
However, the Bank confirmed that they would be "monitoring developments closely" and could make an interest rate decision in November.
Further drops in the pound could have an impact on the housing market, with Virgin Money and Skipton Building Society having halted mortgage offers for new customers. Halifax has also said that it would stop mortgages which include product fees.