The ICM poll for The Guardian - released days ahead of crucial by-elections in Copeland and Stoke Central - put Tories on 44 per cent nationwide (up two points since a similar survey two weeks ago) and Labour on 26 per cent (down one).
The Tories have enjoyed a larger lead in just three polls in this series, which dates back to 1983, said ICM.
Two of these came shortly before the 1983 general election, when Michael Foot went down to a crushing defeat at the hands of Margaret Thatcher, and the other at a low-point in Gordon Brown’s premiership in 2008.
Labour’s support was just one point above its worst ratings in the series - 25 per cent in June 2008 and August 2009. But Conservatives remain below their peak of 47.5 per cent recorded in 1983.
Ukip was up one point on 13 per cent and Liberal Democrats down two on 8 per cent, while Greens were unchanged at 4 per cent.
• ICM Unlimited interviewed 2,028 adults between 17 and 19 February 2017.