Tory support has hit its highest level for the party since 2017, according to the rolling average of opinion polls.
Support for Labour has also grown significantly ahead of the December 12 general election, according to the latest SavantaComRes poll.
The survey put the Conservatives at 41 per cent on Saturday evening, up one percent from Friday.
Labour remained eight points behind but rose three points to 33 per cent, its highest level since April.
Meanwhile, support for Nigel Farage's Brexit party hit a new low, sinking from seven to five per cent.
It follows his announcement he would withdraw candidates from seats won by the Conservatives in 2017 to help Prime Minister Boris Johnson deliver Brexit.
The Liberal Democrats also saw a drop in support to 14 per cent, after starting at 19 per cent when the election was called.
Mr Johnson made his first keynote speech in the general election campaign this week, pledging to drive a clean energy revolution while investing in the NHS, cutting crime and helping people with the cost of living if he wins on December 12.