Above is the Wikipedia polling chart showing how things have moved in the GB national opinion polls since the December 2019 General Election. The trend lines are local regressions.
The overall picture is pretty clear and it shows the huge task facing the new Tory leader as she/he takes over on Tuesday. On these numbers the Tories are going to struggle to retain power. They are helped by the FPTP voting system so that their support is much more evenly spread than LAB which means that Starmer’s party will have to have a significantly bigger lead on overall votes to get into majority territory.
My reckoning is that the Tories can retain control if they can keep overall seat losses down to 47. This assumes that elected Sinn Fein MPs continue to refuse to sit at Westminster for the seats they win in Northern Ireland.
Also the new boundaries are going to help the Tories and we are going to see much more analysis on that as we get closer to the election.
There has been speculation that Liz Truss, if indeed it is her, is considering an early election. She’s certainly not going to do anything like that while the polls have the party trailing. The memory of TMay at GE2017 is still very strong. She had polling leads of 20%+ when she called the election which ended with the party losing its overall majority.