Research group Opinium published the result of the online poll on Saturday, a day after May said the result of the country’s upcoming national election is “not certain.”
About 45 percent of voters said they would vote for the Conservative Party, which is up 7 percent on last week, while support for Labour stood at 26 percent, 3 percentage points down, according to the poll of 2,003 voters.
The pro-Brexit UK Independence Party (UKIP) gained 9 percent of voter support, which is 5 points down from the last week. The Liberal Democrats climbed up 4 points to 11 percent.
In a surprise move on Tuesday, May called a snap election to be held in June in order to bolster her position before going into two years of negotiations with the European Union about Britain’s departure from the bloc.
The Conservative lead is enough to win a majority that could be over 100 seats, but Prime Minister May said on Friday she was not complacent.
"The election campaign has only just begun. I'm not taking anything for granted. The result is not certain," she said on Friday in a speech at a GlaxoSmithKline factory in her constituency of Maidenhead.
Conservatives are leading because the Labour party has been marred by divisions over its leader Jeremy Corbyn and Brexit.
Lawmakers in the UK Parliament’s House of Commons voted 522 to 13 on Wednesday in favor of a motion put forward by May for a “snap” election.
The election will be held on June 8, nearly a year after 52 percent of Britons voted to leave the European Union. The current Parliament will dissolve on June 3.
May said an early election will bolster the UK’s position in talks over Brexit and is in the country’s national interest. Despite this, she had repeatedly said in the past that she would not seek a new election before 2020.
Influential figures like former Prime Minister Tony Blair argue that May made the call because she knew the Labour Party is in a disadvantaged situation.